Poor Fusion Rates Following Cervical Corpectomy Reconstructed With an Expandable Cage: Minimum 2-Year Radiographic and Clinical Outcomes

BACKGROUND

Expandable cages are often used to reconstruct cervical corpectomies but there are few long-term follow-up studies with large numbers.

OBJECTIVE

To analyze the clinical and radiographic results of cervical corpectomy reconstructed with expandable cages for degenerative stenosis.

METHODS

We performed a retrospective analysis of 78 patients with degenerative cervical stenosis treated with a corpectomy reconstructed with an expandable cage. We evaluated the clinical and radiographic outcomes, as well as complications of the procedure at a minimum 2-yr follow-up.

RESULTS

There was a decrease in the visual analog scale pain average from 75 mm to 8.5 mm (P = .02); a decrease in the Neck Disability Index average from 55% to 12% (P = .009); and improvement in the Japanese Orthopaedic Association average from 12 to 14 points (P = .01). There was a change in cervical lordosis (Cobb method) average from −9.3° to −15.1° (P = .002), without significant loss of lordosis (P = .63). The fusion rate, by criteria of the Cervical Spine Research Society (CSRS), was low: using dynamic X-rays – 50% (n = 39/78) and using computed tomography (CT) – 47.4% (n = 37/78). A total of 11 patients (14.1%) suffered complications.

CONCLUSION

To our knowledge, this is the largest series (78) with a minimum 2-yr follow-up in the literature and the first using the dynamic radiographic and CT criteria endorsed by the CSRS. Using these criteria, our fusion rates were much lower than all previous reports in the literature. Despite this, patient-reported outcomes were reasonable. There was a relatively low incidence of perioperative complications, most of which were likely not implant-specific and there was only 1 case of implant failure.

The Telehealth Spine Physical Examination: A Practical Approach Learned During the COVID-19 Pandemic

Background

The COVID-19 pandemic has led to a surge in the use of telehealth visits across the country to minimize in-person visits and to limit the spread of COVID-19. To date, no standards or outlines for telehealth spine examinations have been detailed and many surgeons simply defer the physical examination when performing telehealth visits. Nevertheless, just as physical examination of the spine is an integral part of live clinical encounters, appropriately modified physical examinations should also be part of virtual visits.

Methods

In this study we provide our methodology for guiding providers and patients in efficiently performing telehealth spine examinations.

Results

The study details steps for efficiently performing a physical examination in the telehealth setting. Our written suggestions are supplemented with photographs and video recordings to help streamline the virtual examination.

Conclusions

An effective and efficient spine physical examination can be performed during telehealth visits. Future directions include verifying the findings from our virtual physical examination with in-person examinations.

The Intersection Between Lateral Mass and Inferomedial Edge of the C1 Posterior Arch: A Reference Point for C1 Lateral Mass Screw Insertion

Objective

To determine the ideal Atlas (C1) lateral mass screw placement and trajectory using the intersection between the lateral mass and inferomedial edge of the posterior arch as an easily identifiable and reproducible medial reference point. Selection of an ideal entry point and trajectory of C1 lateral mass screw insertion can help to minimize neurovascular injuries. While various techniques for screw insertion have been proposed in the past, they all require extensive dissection of the C1 lateral mass, which can cause profuse bleeding.

Methods

Ninety-three 3-dimensional computed tomography reconstructed images of C1 lateral masses in adult patients were utilized to simulate the placement of C1 lateral mass screws via 4 entry points and 2 trajectory angles referencing off of a medial reference point using Vero’s VISI 17 software. The safety during screw insertion simulation, as well as the screw length, were evaluated.

Results

We found that C1 lateral mass screws could be safely placed bilaterally at 3 mm lateral to the reference point in both 0° and 15° medial screw angulation without violation of the cortex. The 15° medial angulation allowed for longer (18 mm) screws than the 0° angulation.

Conclusion

We recommend starting C1 lateral mass screws 3 mm lateral to the intersection between the lateral mass and inferomedial edge of the posterior arch at a 15° medial angulation.

Circumferential Operations of the Cervical Spine

Generally, a combined anterior and posterior cervical approach is associated with significant morbidity since it requires an extended operative time, greater intraoperative blood loss, and both anterior- and posterior-related surgical complications. However, there are some instances where a circumferential cervical fusion can be advantageous. Our objective is to discuss the indications for circumferential cervical spine procedures. A narrative review of the literature was performed. We include the indications for circumferential cervical approaches of the senior author (KDR). Indications for circumferential approaches include: (1) high-risk patients for pseudoarthrosis, (2) cervical deformity (e.g., degenerative, posttraumatic, cervicothoracic kyphosis), (3) cervical spine metastases (especially those with multilevel involvement), (4) cervical spine infection, (5) unstable cervical trauma, (6) movement disorders and cerebral palsy, (7) Multiply operated patient (especially postlaminectomy kyphosis and patients with massive ossification of the posterior longitudinal ligament), and when (8) early fusion is desirable. Circumferential procedures may be useful in many different cervical spine conditions requiring surgery. Despite its advantages, particularly with reducing the risk for pseudarthrosis, the benefits of a combined approach must be weighed against the risks associated with a dual approach. With appropriate preoperative planning, intraoperative decision-making, and surgical techniques, excellent clinical outcomes can be achieved.

Revision Surgeries at the Index Level After Cervical Disc Arthroplasty - A Systematic Review

Objective

To perform a systematic literature review on revision surgeries at the index level after cervical disc arthroplasty (CDA) failure.

Methods

A systematic literature review was performed according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Prospective studies on patients who required a secondary surgery after CDA failure were included for analysis. The minimum follow-up for these studies was 5 years.

Results

Out of 864 studies in the original search group, a total of 20 studies were included. From a total of 4,087 patients, 161 patients required a reoperation at the index level. A total of 170 surgeries were performed, as some patients required multiple surgeries. The most common secondary procedures were anterior cervical discectomy and fusion (ACDF) (68%, N = 61) and posterior cervical fusion (15.5%, N = 14), followed by other reoperation (13.3%, N = 12). The associated outcomes for those who required a revision surgery were rarely mentioned in the included literature.

Conclusion

The long-term revision rate at the index level of failed CDA surgery was 3.9%, with a minimum 5-year follow-up. ACDF was the most commonly performed procedure to salvage a failed CDA. Some patients who required a new surgery after CDA failure may require a more extensive salvage procedure and even subsequent surgeries.

Predictors of neurologic outcome after surgery for cervical ossification of the posterior longitudinal ligament differ based on myelopathy severity: a multicenter study

OBJECTIVE

The purpose of this retrospective multicenter study was to compare prognostic factors for neurological recovery in patients undergoing surgery for cervical ossification of the posterior longitudinal ligament (OPLL) based on their presenting mild, moderate, or severe myelopathy.

METHODS

The study included 372 consecutive patients with OPLL who underwent surgery for cervical myelopathy between 2006 and 2016 in East Asian countries with a high OPLL prevalence. Baseline and postoperative clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) myelopathy score and recovery ratio. Radiographic assessment included occupying ratio, cervical range of motion, and sagittal alignment parameters. Patient myelopathy was classified as mild, moderate, or severe based on the preoperative JOA score. Linear and multivariate regression analyses were performed to identify patient and surgical factors associated with neurological recovery stratified by baseline myelopathy severity.

RESULTS

The mean follow-up period was 45.4 months (range 25-140 months). The mean preoperative and postoperative JOA scores and recovery ratios for the total cohort were 11.7 ± 3.0, 14.5 ± 2.7, and 55.2% ± 39.3%, respectively. In patients with mild myelopathy, only age and diabetes correlated with recovery. In patients with moderate to severe myelopathy, older age and preoperative increased signal intensity on T2-weighted imaging were significantly correlated with a lower likelihood of recovery, while female sex and anterior decompression with fusion (ADF) were associated with better recovery.

CONCLUSIONS

Various patient and surgical factors are correlated with likelihood of neurological recovery after surgical treatment for cervical OPLL, depending on the severity of presenting myelopathy. Older age, male sex, intramedullary high signal intensity, and posterior decompression are associated with less myelopathy improvement in patients with worse baseline function. Therefore, myelopathy-specific preoperative counseling regarding prognosis for postoperative long-term neurological improvement should include consideration of these individual and surgical factors.

Effect of Ventral vs Dorsal Spinal Surgery on Patient-Reported Physical Functioning in Patients With Cervical Spondylotic Myelopathy: A Randomized Clinical Trial

IMPORTANCE

Cervical spondylotic myelopathy is the most common cause of spinal cord dysfunction worldwide. It remains unknown whether a ventral or dorsal surgical approach provides the best results.

OBJECTIVE

To determine whether a ventral surgical approach compared with a dorsal surgical approach for treatment of cervical spondylotic myelopathy improves patient-reported physical functioning at 1 year.

DESIGN, SETTING, AND PARTICIPANTS

Randomized clinical trial of patients aged 45 to 80 years with multilevel cervical spondylotic myelopathy enrolled at 15 large North American hospitals from April 1, 2014, to March 30, 2018; final follow-up was April 15, 2020.

INTERVENTIONS

Patients were randomized to undergo ventral surgery (n = 63) or dorsal surgery (n = 100). Ventral surgery involved anterior cervical disk removal and instrumented fusion. Dorsal surgery involved laminectomy with instrumented fusion or open-door laminoplasty. Type of dorsal surgery (fusion or laminoplasty) was at surgeon's discretion.

MAIN OUTCOMES AND MEASURES

The primary outcome was 1-year change in the Short Form 36 physical component summary (SF-36 PCS) score (range, 0 [worst] to 100 [best]; minimum clinically important difference = 5). Secondary outcomes included 1-year change in modified Japanese Orthopaedic Association scale score, complications, work status, sagittal vertical axis, health resource utilization, and 1- and 2-year changes in the Neck Disability Index and the EuroQol 5 Dimensions score.

RESULTS

Among 163 patients who were randomized (mean age, 62 years; 80 [49%] women), 155 (95%) completed the trial at 1 year (80% at 2 years). All patients had surgery, but 5 patients did not receive their allocated surgery (ventral: n = 1; dorsal: n = 4). One-year SF-36 PCS mean improvement was not significantly different between ventral surgery (5.9 points) and dorsal surgery (6.2 points) (estimated mean difference, 0.3; 95% CI, -2.6 to 3.1; P = .86). Of 7 prespecified secondary outcomes, 6 showed no significant difference. Rates of complications in the ventral and dorsal surgery groups, respectively, were 48% vs 24% (difference, 24%; 95% CI, 8.7%-38.5%; P = .002) and included dysphagia (41% vs 0%), new neurological deficit (2% vs 9%), reoperations (6% vs 4%), and readmissions within 30 days (0% vs 7%).

CONCLUSIONS AND RELEVANCE

Among patients with cervical spondylotic myelopathy undergoing cervical spinal surgery, a ventral surgical approach did not significantly improve patient-reported physical functioning at 1 year compared with outcomes after a dorsal surgical approach.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02076113.

Comparison of adverse events between cervical disc arthroplasty and anterior cervical discectomy and fusion: a 10-year follow-up

BACKGROUND CONTEXT

Cervical disc arthroplasty (CDA) has been advocated as an alternative to anterior cervical discectomy and fusion (ACDF) with the added potential to reduce the risk of adjacent level disc degeneration and segmental instability. However, the long-term adverse events of arthroplasty have yet to be fully reported.

PURPOSE

To investigate the 10-year follow-up adverse events rates between CDA and ACDF.

STUDY DESIGN/SETTING

The study was a randomized, prospective, multicenter Investigational Device Exemption (IDE) trial and its continued follow-up as a postapproval study (PAS). Single level surgeries were performed for cervical disc pathologies between May 2002 and October 2004.

PATIENT SAMPLE

n=463 patients.

OUTCOME MEASURES

Adverse events comparison of CDA and ACDF from self-reported and physiologic measures.

METHODS

At each evaluation time point, subjects were queried for adverse events since their last visit; and all adverse events were documented, regardless of whether or not they appeared related to the surgery or device. Adverse events were recorded, categorized, and assessed for severity and relationship to the study device and/or surgical procedure. The 10-year cumulative rates for each type of adverse events were summarized using a life-table method for the time-to-event analysis. A log-rank test was used to compare the two treatment groups.

RESULTS

A total of 242 patients received CDA and 221 patients received ACDF. At 10-year follow-up, 54% (130/242) of CDA patients and 47% (104/221) of the ACDF subjects were evaluated. At up to 10-year follow-up, 231 patients in the CDA group (cumulative rate 98.4%) and 199 patients in the ACDF group (cumulative rate 98.7%) had at least one adverse event. Overall, the difference in the cumulative rate of all adverse events over 10 years was not statistically different (p=0.166). The cumulative rates of the following adverse events were not different between the two groups for cancer, cardiovascular, death, dysphonia/dysphagia, gastrointestinal, infection, urogenital, respiratory, implant displacement/loosening, implant malposition, neck and arm pain, neurological, other pain, spinal events, and intraoperative vascular injury. However, there were more adverse events in the CDA group resulting from trauma (p=.012) and more spinal events at the index level (p=.006). The ACDF group had significantly more nonunion events (p=.019), and nonunion outcome pending (p=.034), adjacent level spinal events (p=.033), and events that fell into the "other" category (p=.015).

CONCLUSIONS

The cumulative rates of patients who had any adverse events were not different between the artificial cervical disc and the anterior cervical arthrodesis groups. In addition, the cumulative rates were not different between the two groups for the majority of categories as well.

Development of Neuromonitoring Pedicle Screw - Results of Electrical Resistance and Neurophysiologic Test in Pig Model

Objective

To analyze the electrical resistance of a newly developed neuromonitoring pedicle screw (Neuro-PS) and to verify the electrophysiologic properties of the Neuro-PS in a pig model.

Methods

We developed 2 types of the Neuro-PS in which a gold lead was located internally (type I) and externally (type II). We measured the electrical resistance of the Neuro-PS and the conventional screw and analyzed the electrical thresholds of triggered EMG (t-EMG) of each screw by intentionally penetrating the medial pedicle wall and contacting the exiting nerve root in a pig model.

Results

The electrical resistances of the Neuro-PS were remarkably lower than that of the conventional screw. In electrophysiologic testing, only the type II Neuro-PS under the leadnerve contact condition showed a significantly lower stimulation threshold as compared to the conventional screw.

Conclusion

The Neuro-PS demonstrated lower electrical resistances than the conventional screw. The type II Neuro-PS under the lead-nerve contact condition showed a significantly lower stimulation threshold compared to that of the other screws in the t-EMG test.

Does screw length for primary two-level ACDF influence pseudarthrosis risk?

BACKGROUND CONTEXT

Pseudarthrosis remains a major complication for patients undergoing anterior cervical discectomy and fusion (ACDF; 0%-15% at 1-year follow-up). Potentially modifiable risk factors are known in literature, such as smoking and osteoporosis. Biomechanical studies suggest that plates with locking screws can enhance the fixation rigidity and pull-out strength. Although longer screws are known to be correlated with increased pull-out strength, deeper screw depths can increase the risk for intraoperative complications. An important factor that has yet to be studied is the minimum screw length relative to the diameter of the vertebral body (VB) necessary to achieve successful fusion. In this study, we hypothesize that screws with shorter depths relative to the VB will increase the risk for radiographic pseudarthrosis and result in poor patient reported outcomes (PROs).

PURPOSE

To examine the impact of ACDF screw length on pseudarthrosis risk.

STUDY DESIGN

A review of prospectively collected data.

PATIENT SAMPLE

A total of 85 patients were included in this study. The mean age ±standard deviation was 58.9±10.3 and 42.4% of patients were female. The mean follow-up was 21.6±8.3 months.

OUTCOME MEASURES

The neck disability index (NDI) was used to assess PROs up to 2-years after surgery. For each ACDF level, the screw length and VB% (screw length divided by the anterior-posterior VB diameter) were measured. Radiographic pseudarthrosis (interspinous motion [ISM] ≥1 mm) was recorded at 6-weeks, 6-months, and 1-year for each patient. The positive and negative predictive values (PPV, NPV) for ISM ≥ 1mm were measured for different VB% thresholds. A VB% of <75% was found to have the highest PPV (93%) and NPV (70%) for radiographic pseudarthrosis. This threshold of <75% was then assessed in our bivariate and multivariate analyses.

METHODS

We reviewed a database (2015-2018) of adult (≥18 years old) patients who underwent a primary two-level ACDF with or without corpectomy. All ACDF constructs involved fixed angle screws. The minimum follow-up period was 1 year. Multivariate analyses were performed to determine if screw VB% was an independent risk factor for radiographic pseudarthrosis.

RESULTS

By 1-year, overall fusion success was achieved in 92.9% of patients. The 1-year revision rate was 4.7%. Patients with any screw VB% <75% had substantially worse fusion success (64.3%) than those who did not (98.6%) at 1-year. The VB% <75% increased the risk for radiographic pseudarthrosis at every follow up period. In comparison to other time-points, patients with radiographic pseudarthrosis at 6 weeks had significantly worse NDI scores by 2-years (p=.047). The independent risk factors for radiographic pseudarthrosis at 6-weeks included any screw VB% <75% (OR 77, p<.001), prior/current smoker (OR 6.8, p=.024), and corpectomy (OR 0.1, p=.010). Patients with ISM≥1 mm had a higher rate of revision surgery at 1-year (5.9% vs. 3.9%), but this was not statistically significant (p=.656).

CONCLUSIONS

In primary two-level ACDF, VB% <75% is significantly associated with increased ISM (≥1 mm) at all time points for this study. As an intraoperative guide, spine surgeons can use the screw VB% threshold of <75% to avoid unnecessarily short screws. This threshold can be easily measured pre- and intraoperatively, and has been found to be strongly correlated to radiographic pseudarthrosis in the early postoperative period.

Recent trends in medicare utilization and reimbursement for anterior cervical discectomy and fusion

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) has been considered the gold standard for treating various cervical spine pathologies stemming from cervical degenerative disorders. While cervical artificial disc replacement has emerged as an alternative in select cases, ACDF still remains a commonly performed procedure.

PURPOSE

This study seeks to define the costs of ACDF and identify trends and variations in ACDF volume, utilization, and surgeon and hospital reimbursement rates.

STUDY DESIGN/SETTING

Retrospective analysis of patients undergoing ACDF PATIENT SAMPLE: Medicare patients undergoing ACDF between 2012 and 2017 OUTCOME MEASURES: ACDF volume, utilization rates, and surgeon/hospital reimbursement rates METHODS: This study tracked annual Medicare claims and payments to ACDF surgeons using publicly-available databases and aggregated data at the county level. Descriptive statistics and multivariate regression models were used to evaluate trends in procedure volume, utilization rates (per 10,000 Medicare beneficiaries), and reimbursement rates, and to examine associations between county-specific variables (ie, urban or rural, average household income, poverty rate, percent Medicare population, race/ethnicity demographics), and ACDF utilization and reimbursement rates.

RESULTS

A total of 264,673 ACDF surgeries were performed in the Medicare population from 2012 to 2017, with a 24.2% increase in annual procedure volume. Utilization also increased by 6.5% from 8.0 surgeries per 10,000 Medicare beneficiaries in 2012 to 8.5 in 2017. Hospital reimbursements for cervical spine fusion surgeries without complications or co-morbidities experienced nominal and inflation-adjusted increases of 9.5% and 0.7%, respectively, from $12,030.11 in 2012 to $13,167.64 in 2017. Surgeon reimbursements for single-level and multilevel ACDF each nominally decreased from $958.11 and $1,173.01, respectively, in 2012 to $950.34 and $1,138.41 in 2017 (a 0.8% and 2.9% decrease, respectively), but after adjusting for inflation, reimbursements per case fell by an average of 8.7% and 10.7%, respectively. In contrast, mean reimbursements per case for hospitals rose by 7.1% (1.5% inflation-adjusted decrease). A significant upward yearly trend in ambulatory surgical centers volume, resulted in a net increase of 184.5% between 2015 and 2017 (p<.001).

CONCLUSIONS

While ACDF volume and utilization has continued to increase since 2012, Medicare payments to hospitals and surgeons have struggled to keep up with inflation. Our study confirms that Medicare reimbursement per case continues to decrease at a disproportionate rate for surgeons, compared to hospitals. The increasing trend in procedures performed at ambulatory surgical centers shows promise for a future model of cost-efficient and value-based care.

Symptomatic cervical spinal stenosis in spastic cerebral palsy

AIM

To describe the prevalence of symptomatic cervical spinal stenosis (CSS) in spastic cerebral palsy (CP) and associated characteristics.

METHOD

This cross-sectional study of adults (>18y) with CP (2006-2016) at a single institution compared the patient characteristics (demographics, comorbidities, surgical history, medications, Gross Motor Function Classification System [GMFCS] level, and CP type) of patients with and without CSS.

RESULTS

Of 424 patients (mean age 33y 4mo, SD 13y 6mo, range 18-78y; 225 females, 199 males), 32 patients (7.5%) had symptomatic CSS. GMFCS levels in the study cohort were distributed as follows: level I, 25%; level II, 25%; level III, 22%; level IV, 19%; level V, 9%. Twenty-five out of 32 (78.1%) patients had spastic CP, two (6.3%) had dystonic CP, and one (3.1%) had mixed characteristics. Individuals with CSS were older (mean age 54y 6mo, SD 10y 5mo vs mean age 31y 7mo, SD 12y 1mo, p<0.05) and had a higher body mass index (26.1, SD 4.8 vs 23.4, SD 6.2, p<0.05) than those without CSS. Presentations included upper-extremity symptoms (73%), ambulation decline (70%), neck pain (53%), and incontinence (30%). Common stenosis levels were C5-C6 (59%), C4-C5 (56%), and C6-C7 (53%).

INTERPRETATION

Symptomatic CSS was identified in 7.5% of this adult cohort during the 2006 to 2016 period. Diagnosis in CP is difficult due to impaired communication and pre-existing gait abnormalities and spasticity. Given the high prevalence of symptomatic CSS in adults, we propose developing screening guidelines. Physicians must maintain a high level of suspicion for CSS if patients present with changes in gait or spasticity.

Timing of Surgery in Thoracolumbar Spine Injury: Impact on Neurological Outcome

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

We aimed to evaluate the improvement in neurological deficit following early versus late decompression and stabilization of thoracolumbar junctional fractures.

METHODS

This is a retrospective evaluation of all patients with a traumatic spinal cord injury (SCI) from T11 to L2 treated at a teaching hospital between 2010 and 2017. Grouped analysis was performed comparing the cohort of patients who received early surgery within 24 hours (group 1) with those operated within 24 to 72 hours (group 2) and more than 72 hours after SCI (group 3). The primary outcome was the change in ASIA (American Spinal Injury Association) motor score at 12-month follow-up.

RESULTS

There were 317 patients (225 males and 92 females with mean age of 31.55 ± 12.43 years). A total of 144, 77, and 96 patients belonged to groups 1, 2, and 3 respectively. Improvement of at least 1 grade on ASIA classification was observed in 80, 45, and 33 patients in groups 1, 2, and 3 respectively (P = .001). Overall, 32, 12, and 10 patients improved ≥2 grades on ASIA classification in groups 1, 2, and 3, respectively (P = .069). On logistic regression analysis, early surgery and severity of initial injury (complete [ASIA A] vs incomplete SCI [ASIA B-D]) were found to significantly influence the potential for neurologic improvement (P = .004 and P < .0001, respectively).

CONCLUSION

We believe that the earlier the decompression, the better. The 72-hour cutoff represents the most promising time window during which surgical decompression has the potential to confer a neuroprotective effect in the setting of incomplete SCI (ASIA B-D) in the distal region of the spinal cord (conus medullaris).

Osteolysis after cervical disc arthroplasty

PURPOSE

Cervical disc arthroplasty (CDA) has become an increasingly popular treatment for cervical degenerative disc disease. One potential complication is osteolysis. However, current literature on this topic appears limited. The purpose of this study is to elucidate the incidence, aetiology, consequence, and subsequent treatment of this complication.

METHODS

A systematic literature review was performed according to the PRISMA guidelines. Studies discussing the causes, incidence and management of osteolysis after a CA were included.

RESULTS

A total of nine studies were included. We divided these studies into two groups: (1) large case series in which an active radiological evaluation for osteolysis was performed (total = six studies), (2) case report studies, which discussed symptomatic cases of osteolysis (total = three). The incidence of asymptomatic osteolysis ranged from 8 to 64%; however, only one study reported an incidence of < 10% and when this case was excluded the incidence ranged from 44 to 64%. Severe asymptomatic bone loss (exposure of the implant) was found in less than 4% of patients. Bone loss from osteolysis appeared to occur early (< 1 year) after surgery and late (> 1 year) as well. Symptomatic patients with osteolysis often required revision surgery. These patients required removal of implant and conversion to fusion in the majority of the cases.

CONCLUSIONS

Osteolysis after CDA is common; however, the majority of cases have only mild or asymptomatic presentations that do not require revision surgery. The timing of osteolysis varies significantly. This may be due to differences in the aetiology of osteolysis.

Addressing a national crisis: the spine hospital and department's response to the COVID-19 pandemic in New York City

In a very brief period, the COVID-19 pandemic has swept across the planet leaving governments, societies, and healthcare systems unprepared and under-resourced. New York City now represents the global viral epicenter with roughly one-third of all mortalities in the United States. To date, our hospital has treated thousands of COVID-19 positive patients and sits at the forefront of the United States response to this pandemic. The goal of this paper is to share the lessons learned by our spine division during a crisis when hospital resources and personnel are stretched thin. Such experiences include management of elective and emergent cases, outpatient clinics, physician redeployment, and general health and wellness. As peak infections spread across the United States, we hope this article will serve as a resource for other spine departments on how to manage patient care and healthcare worker deployment during the COVID-19 crisis.

Safety of Outpatient Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) is being increasingly offered on an outpatient basis. However, the safety profile of outpatient ACDF remains poorly defined.

OBJECTIVE

To review the medical literature on the safety of outpatient ACDF.

METHODS

We systematically reviewed the literature for articles published before April 1, 2018, describing outpatient ACDF and associated complications, including incidence of reoperation, stroke, thrombolytic events, dysphagia, hematoma, and mortality. A random-effects analysis was performed comparing complications between the inpatient and outpatient groups.

RESULTS

We identified 21 articles that satisfied the selection criteria, of which 15 were comparative studies. Most of the existing studies were retrospective, with a lack of level I or II studies on this topic. We found no statistically significant difference between inpatient and outpatient ACDF in overall complications, incidence of stroke, thrombolytic events, dysphagia, and hematoma development. However, patients undergoing outpatient ACDF had lower reported reoperation rates (P < .001), mortality (P < .001), and hospitalization duration (P < .001).

CONCLUSION

Our meta-analysis indicates that there is a lack of high level of evidence studies regarding the safety of outpatient ACDF. However, the existing literature suggests that outpatient ACDF can be safe, with low complication rates comparable to inpatient ACDF in well-selected patients. Patients with advanced age and comorbidities such as obesity and significant myelopathy are likely not suitable for outpatient ACDF. Spine surgeons must carefully evaluate each patient to decide whether outpatient ACDF is a safe option. Higher quality, large prospective randomized control trials are needed to accurately demonstrate the safety profile of outpatient ACDF.

Occipitocervical Fixation: General Considerations and Surgical Technique

STUDY DESIGN

Narrative literature review.

OBJECTIVE

To review and present details on the occipitocervical fixation (OCF) technique as well as considerations for planning the procedure.

METHODS

We present the surgical technique of OCF in a step-by-step didactic and practical manner with surgical tips and tricks, including C1 and C2 screw fixation techniques. Additionally, we discuss complications, the extension of fusion, types of OCF, and how to avoid common side effects associated with OCF.

RESULTS

The complex and mobile anatomy of the craniocervical junction, when requiring fixation and fusion, warrants rigid instrumentation that can be achieve using a modern screw-plate-rod construct. Indications for OCF are craniocervical instability, and atlantoaxial instability when selective atlantoaxial fusion is not feasible. OCF generally involves occiput-C2 fusion. C1 fixation is generally unnecessary, since it increases the surgical time and is associated with the risk of vascular complications. Selective occiput-C2 fusion is recommended when there is no need for including the cervical subaxial region (eg, when stenosis or fractures coexist in the subaxial spine), and good fixation is achieved at C2. Most instrumentation systems now have occipital plates that are not pre-integrated to rods, making fixation much simpler. Surgical steps, from position to wound closure, are presented in detail, with pearls for practice and discussion of cervical alignment.

CONCLUSIONS

OCF is a challenging procedure, with potential risk of severe adverse effects. Understanding the surgical indications, as well as the nuances of the surgical technique, is required to improve patient outcomes and avoid complications.

Perioperative Anticoagulation Management in Spine Surgery: Initial Findings From the AO Spine Anticoagulation Global Survey

STUDY DESIGN

Cross-sectional, international survey.

OBJECTIVES

This study addressed the global perspectives concerning perioperative use of pharmacologic thromboprophylaxis during spine surgery along with its risks and benefits.

METHODS

A questionnaire was designed and implemented by expert members in the AO Spine community. The survey was distributed to AO Spine's spine surgeon members (N = 3805). Data included surgeon demographic information, type and region of practice, anticoagulation principles, different patient scenarios, and comorbidities.

RESULTS

A total of 316 (8.3% response rate) spine surgeons completed the survey, representing 64 different countries. Completed surveys were primarily from Europe (31.7%), South/Latin America (19.9%), and Asia (18.4%). Surgeons tended to be 35 to 44 years old (42.1%), fellowship-trained (74.7%), and orthopedic surgeons (65.5%) from academic institutions (39.6%). Most surgeons (70.3%) used routine anticoagulation risk stratification, irrespective of geographic location. However, significant differences were seen between continents with anticoagulation initiation and cessation methodology. Specifically, the length of a procedure (P = .036) and patient body mass index (P = .008) were perceived differently when deciding to begin anticoagulation, while the importance of medical clearance (P < .001) and reference to literature (P = .035) differed during cessation. For specific techniques, most providers noted use of mobilization, low-molecular-weight heparin, and mechanical prophylaxis beginning on postoperative 0 to 1 days. Conversely, bridging regimens were bimodal in distribution, with providers electing anticoagulant initiation on postoperative 0 to 1 days or days 5-6.

CONCLUSION

This survey highlights the heterogeneity of spine care and accentuates geographical variations. Furthermore, it identifies the difficulty in providing consistent perioperative anticoagulation recommendations to patients, as there remains no widely accepted, definitive literature of evidence or guidelines.

Curved versus straight-cut hinges for open-door laminoplasty: A finite element and biomechanical study

In this study, the stabilities of the hinge sides of plate-augmented open-door laminoplasties based on cutting in a curved or straight line were compared using a finite element (FE) model and an experimental assessment. Using FE models generated from CT scans of a human subject, straight and curved techniques for cutting the hinge side were evaluated. Compressive forces were applied to both simulated models, and the stress distributions on the respective hinge sites were evaluated by comparing the maximum von Mises stresses. Biomechanical testing procedures were then carried out on porcine cervical vertebrae, with straight- and curved-cut groups loaded to failure, and the corresponding reaction forces on the hinge sites were recorded using a loading cell. The FE analysis results revealed no significant differences between the straight- and curved-cut groups in terms of maximum stress forces on the superior, middle, or inferior portions of the hinge sites. In the experimental study, the curved-cut group withstood higher loads to failure at the hinge site than the straight-cut group. The ability of the curved-cut laminoplasty hinges to withstand higher compressive loading to failure than straight-cut hinges suggests the potential of the proposed technique to reduce the risk of hinge fracture and displacement.

Anterior osteotomy for rigid cervical deformity correction

Rigid deformities of the cervical spine can be associated with significant pain, disability, and impaired quality of life. Historical treatments generally utilized posterior approaches including the opening wedge osteotomy and pedicle subtraction osteotomy (PSO). Translation can occur during osteoclasis of the opening wedge osteotomy, making it inherently less stable than a PSO. The PSO is limited to lower cervical or upper thoracic levels due to the vertebral artery and sensitivity of cervical nerve roots to compression during osteotomy closure. The anterior osteotomy, defined as an osteotomy through the cervical disc space and uncovertebral joints back to the level of the transverse foramen bilaterally, is a powerful correction technique that can be applied throughout the cervical spine. It can also be used to correct deformities in the coronal plane. This review will summarize the technical nuances of the anterior osteotomy including patient selection, preoperative planning, and surgical technique.

Improvements in Neck Pain and Disability Following C1-C2 Posterior Cervical Instrumentation and Fusion for Atlanto-Axial Osteoarthritis

OBJECTIVE

Symptomatic Atlanto-axial (C1-2) osteoarthritis (AAOA) is a common phenomenon in elderly patients; however, there is a paucity of data on the effectiveness of posterior atlanto-axial fusion (PAAF) for this condition. To this end, here we assess changes in patient-reported outcomes and neck-related disability in adult patients undergoing PAAF for symptomatic C1-2 AAOA.

METHODS

In this retrospective study, the clinical records of consecutive patients with symptomatic AAOA who underwent PAAF between 2004 and 2017 were reviewed. Patient demographics, comorbidities, intraoperative and postoperative variables, and complication rates were collected. Neck Disability Index (NDI) scores were recorded at baseline and 6 weeks, 6 months, 1 year, and 2 years postoperatively.

RESULTS

Forty-two patients (average age, 72.04 ± 8.56 years; 26.19% males) met the study's inclusion criteria. In this cohort, 19.04% had previous subaxial cervical spine surgery, 35.71% had a history of smoking (all had stopped smoking before surgery), and 11.90% had type II diabetes. At baseline, the majority of patients had a normal neurologic exam. The average preoperative NDI score was 26.88 ± 24.85, which improved to 10.59 ± 14.88 at the 1-year follow-up and 13.20 ± 14.96 at the 2-year follow-up (P = 0.004). At baseline, 18% of the patients reported severe disability based on NDI score; this percentage decreased to 2% at 1 year and 0 at 2 years (P = 0.01). Importantly, a high percentage (11.90%) of patients had undergone previous subaxial cervical fusion for their pain due to a mistaken diagnosis for this condition, without symptom relief.

CONCLUSIONS

In appropriately selected patients, PAAF may decrease neck pain and improve functional disability in patients with AAOA. Future prospective longitudinal studies are needed to corroborate these findings.