Perioperative and swallowing outcomes in patients undergoing 4- and 5-level anterior cervical discectomy and fusion.

OBJECTIVE: Anterior cervical discectomy and fusion (ACDF) is a common and robust procedure performed on the cervical spine. Literature on ACDF for 4 or more segments is sparse. Increasing the number of operative levels increases surgical complexity, tissue retraction, and risks of complications, particularly dysphagia. The overall risks of these complications and rates of dysphagia are not well studied for surgery on 4 or more segments. In this study, the authors evaluated their institution's perioperative experience with 4- and 5-level ACDFs. METHODS: The authors retrospectively reviewed patients who underwent 4- or 5-level ACDF at their institution over a 6-year period (May 2013-May 2019). Patient demographics, perioperative complications, readmission rates, and swallowing outcomes were recorded. Outcomes were analyzed with a multivariate linear regression. RESULTS: A total of 174 patients were included (167 had 4-level and 7 had 5-level ACDFs). The average age was 60.6 years, and 54.0% of patients (n = 94) were men. A corpectomy was performed in 12.6% of patients (n = 22). After surgery, 56.9% of patients (n = 99) experienced dysphagia. The percentage of patients with dysphagia decreased to 22.8% (37/162) at 30 days, 12.9% (17/132) at 90 days, and 6.3% (5/79) and 2.8% (1/36) at 1 and 2 years, respectively. Dysphagia was more likely at 90 days postoperatively in patients with gastroesophageal reflux (OR 4.4 [95% CI 1.5-12.8], p = 0.008), and the mean (± SD) lordosis change was greater in patients with dysphagia than those without at 90 days (19.8° ± 13.3° vs 9.1° ± 10.2°, p = 0.003). Dysphagia occurrence did not differ with operative implants, including graft and interbody type. The mean length of time to solid food intake was 2.4 ± 2.1 days. Patients treated with dexamethasone were more likely to achieve solid food intake prior to discharge (OR 4.0 [95% CI 1.5-10.6], p = 0.004). Postsurgery, 5.2% of patients (n = 9) required a feeding tube due to severe approach-related dysphagia. Other perioperative complication rates were uniformly low. Overall, 8.6% of patients (n = 15) returned to the emergency department within 30 days and 2.9% (n = 5) required readmission, whereas 1.1% (n = 2) required unplanned return to surgery within 30 days. CONCLUSIONS: This is the largest series of patients undergoing 4- and 5-level ACDFs reported to date. This procedure was performed safely with minimal intraoperative complications. More than half of the patients experienced in-hospital dysphagia, which increased their overall length of stay, but dysphagia decreased over time.

Neurosurgery Resident Wellness and Recovery from Burnout: A 39-Year Single-Institution Experience.

OBJECTIVE: Physician burnout in neurosurgery is highly prevalent and occurs most severely during residency. Although earlier assessments have identified stressors contributing to neurosurgery resident burnout, recovery interventions have not been studied extensively. We aimed to characterize burnout patterns and factors contributing to recovery through a single-institution assessment of neurosurgery residents across 4 decades. METHODS: We administered a 59-item questionnaire to all living current and former residents of a large neurosurgical training institution (n = 96). Respondents indicated the timeline of burnout or hardship during residency and evaluated burnout stressors and recovery factors through a 5-point Likert scale and free-text response. RESULTS: The survey response rate was 67% (64 of 96). The overall self-reported burnout rate was 30% (19 of 64). Recent trainees were significantly more likely to report burnout (P < 0.05). Postgraduate year 2 was cited by 66% of respondents as the onset of burnout or hardship. The most common stressors included work-life imbalance (55%) and imbalance of resident duties (33%). The highest-impact recovery factors were end of a rotation or postgraduate year (80%), increased sleep (48%), and meaningful relationships with colleagues (42%). Institution-specific factors, such as outdoor activities (52%) and intraprogram social events (34%), were also influential in recovery. In free-text responses, respondents identified a strong sense of mission in neurosurgical training as a central driver of recovery to wellness. CONCLUSIONS: Institutional support structures promoting mentorship and camaraderie are actionable methods to encourage resident burnout recovery. This study serves as a model for other programs to identify their "critical periods" of burnout and effective wellness interventions.

History and advances in spinal neurosurgery.

Insight into the historic contributions made to modern-day spine surgery provides context for understanding the monumental accomplishments comprising current techniques, technology, and clinical success. Only during the last century did surgical growth occur in the treatment of spinal disorders. With that growth came a renaissance of innovation, particularly with the evolution of spinal instrumentation and fixation techniques. In this article, the authors capture some of the key milestones that have led to the field of spine surgery today, with an emphasis on the historical advances related to instrumentation, navigation, minimally invasive surgery, robotics, and neurosurgical training.

Odontoid Fusion.

Anterior odontoid screw fixation allows for the internal fixation of unstable odontoid fractures with low morbidity, good fusion rates, and preservation of the atlanto-axial range of motion when applied in appropriate clinical cases. Advances in surgical techniques have allowed for safer, more minimally invasive approaches that reduce the risk of injury to vital prevertebral structures and minimize soft tissue retraction. Moreover, improvements in surgical image guidance technology for spinal surgery that have been applied to odontoid screw placement have helped improve surgeon confidence about exact screw trajectories. In this chapter, we review traditional screw placement techniques and highlight the trends in technical improvements that improve the safety and efficacy of these procedures.

Contribution of Neural Elements to Thoracic Stability.

AIM: Studies of spinal biomechanics typically do not focus on the contributions to range of motion (ROM) of the primary components of the spinal canal, dura, arachnoid, pia, spinal cord, nerve roots, ligaments, and vessels. We sought to determine the stability offered by these soft tissues in vitro. MATERIAL AND METHODS: Human cadaveric segments were tested intact, after osteoligamentous destabilization, and after transection of T8-9 spinal canal components. Specimens were induced into flexion, extension, axial rotation, and lateral bending using non-constraining, non-destructive pure moment while tracking motion response stereophotogrammetrically. The range of motion (ROM) was compared in each condition after adjusting for soft tissue creep. RESULTS: After spinal canal element transection, ROM increased in all directions (mean 4.7%). This increase was most pronounced during lateral bending (p=0.055). The cumulative ROM from all directions of loading showed a statistically significant mean increase of 3.3% (p=0.040). CONCLUSION: Sectioning of canal elements was found to cause a measurable increase in ROM. Although nonviable tissues were tested, living tissues are also likely to contribute to spinal stability.

Biomechanics of Cervical "Skip" Corpectomy Versus Standard Multilevel Corpectomy.

STUDY DESIGN: In vitro biomechanical study of flexibility with finite-element simulation to estimate screw stresses. OBJECTIVE: To compare cervical spinal stability after a standard plated 3-level corpectomy with stability after a plated 3-level "skip" corpectomy where the middle vertebra is left intact (ie, two 1-level corpectomies), and to quantify pullout forces acting on the screws during various loading modes. SUMMARY OF BACKGROUND DATA: Clinically, 3-level cervical plated corpectomy has a high rate of failure, partially because only 4 contact points affix the plate to the upper and lower intact vertebrae. Leaving the intermediate vertebral body intact for additional fixation points may overcome this problem while still allowing dural sac decompression. METHODS: Quasistatic nonconstraining torque (maximum 1 N m) induced flexion, extension, lateral bending, and axial rotation while angular motion was recorded stereophotogrammetrically. Specimens were tested intact and after corpectomy with standard plated and strut-grafted 3-level corpectomy (7 specimens) or "skip" corpectomy (7 specimens). Screw stresses were quantified using a validated finite-element model of C3-C7 mimicking experimentally tested groups. Skip corpectomy with C5 screws omitted was also simulated. RESULTS: Plated skip corpectomy tended to be more stable than plated standard corpectomy, but the difference was not significant. Compared with standard plated corpectomy, plated skip corpectomy reduced peak screw pullout force during axial rotation (mode of loading of highest peak force) by 15% (4-screw attachment) and 19% (6-screw attachment). CONCLUSIONS: Skip corpectomy is a good alternative to standard 3-level corpectomy to improve stability, especially during lateral bending. Under pure moment loading, the screws of a cervical multilevel plate experience the highest pullout forces during axial rotation. Thus, limiting this movement in patients undergoing plated multilevel corpectomy may be reasonable, especially until solid fusion is achieved.

Laminectomy plus Fusion versus Laminectomy Alone for Lumbar Spondylolisthesis.

BACKGROUND: The comparative effectiveness of performing instrumented (rigid pedicle screws affixed to titanium alloy rods) lumbar spinal fusion in addition to decompressive laminectomy in patients with symptomatic lumbar grade I degenerative spondylolisthesis with spinal stenosis is unknown. METHODS: In this randomized, controlled trial, we assigned patients, 50 to 80 years of age, who had stable degenerative spondylolisthesis (degree of spondylolisthesis, 3 to 14 mm) and symptomatic lumbar spinal stenosis to undergo either decompressive laminectomy alone (decompression-alone group) or laminectomy with posterolateral instrumented fusion (fusion group). The primary outcome measure was the change in the physical-component summary score of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36; range, 0 to 100, with higher scores indicating better quality of life) 2 years after surgery. The secondary outcome measure was the score on the Oswestry Disability Index (range, 0 to 100, with higher scores indicating more disability related to back pain). Patients were followed for 4 years. RESULTS: A total of 66 patients (mean age, 67 years; 80% women) underwent randomization. The rate of follow-up was 89% at 1 year, 86% at 2 years, and 68% at 4 years. The fusion group had a greater increase in SF-36 physical-component summary scores at 2 years after surgery than did the decompression-alone group (15.2 vs. 9.5, for a difference of 5.7; 95% confidence interval, 0.1 to 11.3; P=0.046). The increases in the SF-36 physical-component summary scores in the fusion group remained greater than those in the decompression-alone group at 3 years and at 4 years (P=0.02 for both years). With respect to reductions in disability related to back pain, the changes in the Oswestry Disability Index scores at 2 years after surgery did not differ significantly between the study groups (-17.9 in the decompression-alone group and -26.3 in the fusion group, P=0.06). More blood loss and longer hospital stays occurred in the fusion group than in the decompression-alone group (P<0.001 for both comparisons). The cumulative rate of reoperation was 14% in the fusion group and 34% in the decompression-alone group (P=0.05). CONCLUSIONS: Among patients with degenerative grade I spondylolisthesis, the addition of lumbar spinal fusion to laminectomy was associated with slightly greater but clinically meaningful improvement in overall physical health-related quality of life than laminectomy alone. (Funded by the Jean and David Wallace Foundation and others; SLIP ClinicalTrials.gov number, NCT00109213.).

Endoscopic endonasal atlantoaxial transarticular screw fixation technique: an anatomical feasibility and biomechanical study.

OBJECT The primary disadvantage of the posterior cervical approach for atlantoaxial stabilization after odontoidectomy is that it is conducted as a second-stage procedure. The goal of the current study is to assess the surgical feasibility and biomechanical performance of an endoscopic endonasal surgical technique for C1-2 fixation that may eliminate the need for posterior fixation after odontoidectomy. METHODS The first step of the study was to perform endoscopic endonasal anatomical dissections of the craniovertebral junction in 10 silicone-injected fixed cadaveric heads to identify relevant anatomical landmarks. The second step was to perform a quantitative analysis using customized software in 10 reconstructed adult cervical spine CT scans to identify the optimal screw entry point and trajectory. The third step was biomechanical flexibility testing of the construct and comparison with the posterior C1-2 transarticular fixation in 14 human cadaveric specimens. RESULTS Adequate surgical exposure and identification of the key anatomical landmarks, such as C1-2 lateral masses, the C-1 anterior arch, and the odontoid process, were provided by the endonasal endoscopic approach in all specimens. Radiological analysis of anatomical detail suggested that the optimal screw entry point was on the anterior aspect of the C-1 lateral mass near the midpoint, and the screw trajectory was inferiorly and slightly laterally directed. The custommade angled instrumentation was crucial for screw placement. Biomechanical analysis suggested that anterior C1-2 fixation compared favorably to posterior fixation by limiting flexion-extension, axial rotation, and lateral bending (p > 0.3). CONCLUSIONS This is the first study that demonstrates the feasibility of an endoscopic endonasal technique for C1-2 fusion. This novel technique may have clinical utility by eliminating the need for a second-stage posterior fixation operation in certain patients undergoing odontoidectomy.

Instrumentation of the posterior thoracolumbar spine: from wires to pedicle screws.

Over the past 120 years, spinal stabilization has advanced immensely. An updated review highlighting these advancements has not been performed in the past 20 years. The objective of this report is to provide a historical assessment of the decades outlining various key innovators, their techniques, and instrumentation. It is important to provide new generations of surgeons and students with historical evidence of the value of developing new techniques and instrumentation to improve patient care and outcomes.

Spinal metastases due to thyroid carcinoma: an analysis of 202 patients.

BACKGROUND: Spinal metastases (SMs) due to thyroid cancer (TC) are associated with significantly reduced quality of life. The goal of this study is to analyze the clinical manifestations, presentation, and treatments of TC SMs, and to describe specific features of SMs associated with different TC types. PATIENTS AND METHODS: A retrospective analysis of 202 TC SM patients treated at Medstar Washington Hospital Center (37) and collected from the literature (165) was performed. RESULTS: The mean age of patients with SMs was 56.9±14.7 years, and the female-to-male ratio was 2.1:1. Of all patients, 29% (28% of follicular thyroid cancer [FTC] and 37% of papillary thyroid cancer [PTC]) had SMs only. Twenty-nine percent of all patients and 54% of patients with single-site SMs had neither bone non-SMs nor solid organ metastases at the time of presentation. Thirty-five percent of patients had SMs as an initial presentation of TC. TC patients presenting with SMs had a lower rate of other bone and visceral involvement compared with patients whose SMs were diagnosed at the time of thyroid surgery or during follow-up (p<0.05). SMs were more often the initial manifestation of FTC (41% vs. 24%), while PTC SMs were more commonly diagnosed after TC diagnosis (76% vs. 59%; p<0.05). PTC SMs were more frequently diagnosed as synchronous (63% vs. 36% in FTC) versus FTC SMs that developed as metachronous metastases (64% vs. 37% in PTC; p<0.01). All FTC SMs developed within 82 (0-372) months and all PTC SMs within 35 (0-144) months (p<0.01). In FTC SMs as TC manifestation, solid organ metastases involvement was less common than in FTC SMs that were found after TC diagnosis (34% vs. 67%; p<0.01); multisite FTC SMs compared to solitary FTC SMs were associated with the development of other bone nonspinal metastases (82% vs. 30%; p<0.01) and solitary organ metastases (65% vs. 41%; p<0.01). These correlations were not observed in PTC SMs. FTC patients often had neural structure compression (myelopathy/radiculopathy; 72% vs. 36% in PTC), while PTC patients frequently were asymptomatic (38% vs. 5% in FTC; p<0.01). FTC SMs more commonly were (131)I-avid (p<0.01). FTC patients required surgery more frequently (72% vs. 55% in PTC; p<0.05). CONCLUSIONS: Our study reveals that a significant part of TC SMs patients have solitary spinal involvement at the time of presentation and may be considered for aggressive treatment with the intention to improve quality of life and survival. FTC SMs and PTC SMs appear to have distinct presentations, behavior, and treatment modalities, and should be categorized separately for treatment and follow-up planning.

Current treatment modalities for spinal metastases secondary to thyroid carcinoma.

BACKGROUND: The spine is the most common site of bone metastases due to thyroid cancer, which develop in more than 3% of patients with well-differentiated thyroid cancer. Nearly half of patients with bone metastases from thyroid cancer develop vertebral metastases. Spinal metastases are associated with significantly reduced quality of life due to pain, neurological deficit, and increased mortality. SUMMARY: Treatment options for patients with thyroid spinal metastases include radioiodine therapy, pharmacologic therapy, and surgical treatments, with recent advances in radiosurgery and minimally invasive spinal surgery as well. Therapeutic interventions require a multidisciplinary approach and aim to control pain, preserve or improve neurologic function, optimize local tumor control, and improve quality of life. We have proposed a three-tiered approach to the management and practical algorithms for patients with spinal metastases from thyroid carcinoma. CONCLUSIONS: The introduction of novel and improved techniques for the treatment of spinal metastases has created the opportunity to significantly improve control of metastatic tumor growth and the quality of life for the patients with spinal metastases from thyroid cancer. In order for these options to be effectively used, a multidisciplinary approach must be applied in the management of the patients with thyroid spinal metastases.

Technical advances in pediatric craniovertebral junction surgery.

Surgery for conditions in the craniovertebral junction in the pediatric population poses unique challenges. The posterior approach has emerged as the gold standard for arthrodesis in this region. Anterior fixation or decompression also may be indicated. Intraoperative image guidance and neurophysiological monitoring improve the safety and efficacy of these procedures. The specific technical advances in surgery of the craniovertebral junction that have improved patient outcomes are reviewed.

Pediatric craniovertebral junction trauma.

The craniovertebral junction consists of the occiput, atlas, and axis, along with their strong ligamentous attachments. Because of its unique anatomical considerations, trauma to the craniovertebral junction requires specialized care. Children with potential injuries to the craniovertebral junction and cervical spinal cord demand specific considerations compared to adult patients. Prehospital immobilization techniques, diagnostic studies, and spinal injury patterns among young children can be different from those in adults. This review highlights the unique aspects in diagnosis and management of children with real or potential craniovertebral junction injuries.

Radiographic assessment of thoracolumbar fractures based on axial zones.

STUDY DESIGN: Retrospective study of computed tomography imaging of patients with thoracolumbar (TL) fractures. OBJECTIVE: To propose an axial model of spinal fractures based on the osteoligamentous continuity of the TL spinal segments in the axial plane and to determine the correlation between the 3-column theory and the proposed axial zone model. SUMMARY OF BACKGROUND DATA: Predicting spinal instability of TL fractures is based on several radiologic and clinical parameters. Efforts to refine fracture classification schemes to better predict instability continue. METHODS: Computed tomography scans of 229 consecutive patients who presented with TL fractures between March 2005 and April 2007 were reviewed. TL fractures were classified according to both the Denis 3-column theory and the proposed axial zone model. The incidence of column and axial zone injuries was determined. On the basis of these results, a treatment algorithm was developed. RESULTS: Zone disruption in surgical fractures was distributed as follows: 24 (96%) involved zone A, 25 (100%) involved zone B, 17 (68%) involved zone C, and 15 (60%) involved zone D. All surgical fractures involved 2 or more zones. Zone B was involved in all surgical fractures. The likelihood of surgical intervention increased as the number of zones increased, especially if the injury was a 2-column or 3-column injury. CONCLUSIONS: The current 3-column theory of spinal stability does not account for the axial component of an injury. Application of our proposed "axial zone model" may enhance the ability to predict stability, depending not only on the number of columns, but also on the number of zones involved in the injuries. Further clinical and biomechanical studies are warranted to validate this model.