Faculty Bibliography

BACKGROUND:Ossification of the posterior longitudinal ligament (OPLL) may cause cervical myelopathy. In its multilevel form, it may not be easy to manage. Minimally invasive endoscopic posterior cervical decompression may be an alternative to traditional laminectomy surgery. METHODS:Thirteen patients with multilevel OPLL and symptomatic cervical myelopathy were treated with endoscopic spine surgery from January 2019 to June 2020. In this consecutive observational cohort study, pre- and postoperative Japanese Orthopaedic Association (JOA) score and Neck Disability Index (NDI) were analyzed at a final follow-up of 2 years postoperatively. RESULTS:< 0.001). There were no infections, wound complications, or reoperations. CONCLUSION/CONCLUSIONS:Direct posterior endoscopic decompression for multilevel OPLL is feasible in symptomatic patients when executed at a high skill level. While 2-year outcomes were encouraging and on par with historic data obtained with traditional laminectomy, future studies will need to show whether any long-term shortcomings exist.

Personalized care models are dominating modern medicine. These models are rooted in teaching future physicians the skill set to keep up with innovation. In orthopedic surgery and neurosurgery, education is increasingly influenced by augmented reality, simulation, navigation, robotics, and in some cases, artificial intelligence. The postpandemic learning environment has also changed, emphasizing online learning and skill- and competency-based teaching models incorporating clinical and bench-top research. Attempts to improve work-life balance and minimize physician burnout have led to work-hour restrictions in postgraduate training programs. These restrictions have made it particularly challenging for orthopedic and neurosurgery residents to acquire the knowledge and skill set to meet the requirements for certification. The fast-paced flow of information and the rapid implementation of innovation require higher efficiencies in the modern postgraduate training environment. However, what is taught typically lags several years behind. Examples include minimally invasive tissue-sparing techniques through tubular small-bladed retractor systems, robotic and navigation, endoscopic, patient-specific implants made possible by advances in imaging technology and 3D printing, and regenerative strategies. Currently, the traditional roles of mentee and mentor are being redefined. The future orthopedic surgeons and neurosurgeons involved in personalized surgical pain management will need to be versed in several disciplines ranging from bioengineering, basic research, computer, social and health sciences, clinical study, trial design, public health policy development, and economic accountability. Solutions to the fast-paced innovation cycle in orthopedic surgery and neurosurgery include adaptive learning skills to seize opportunities for innovation with execution and implementation by facilitating translational research and clinical program development across traditional boundaries between clinical and nonclinical specialties. Preparing the future generation of surgeons to have the aptitude to keep up with the rapid technological advances is challenging for postgraduate residency programs and accreditation agencies. However, implementing clinical protocol change when the entrepreneur-investigator surgeon substantiates it with high-grade clinical evidence is at the heart of personalized surgical pain management.

BACKGROUND:Spinal cord stimulation (SCS) is a common treatment for neuropathic pain. There are 2 main categories of SCS leads: paddle leads and cylindrical leads. Paddle leads have reduced long-term complications and provide better coverage of target dermatomes when compared to cylindrical leads. However, insertion of a paddle lead requires invasive surgery that comes with significantly higher costs and more short-term complications, such as postoperative pain and infection. In contrast, cylindrical leads can be inserted minimally invasively using percutaneous techniques but provide less coverage of targeted dermatomes and have a higher tendency to migrate from intended neuronal targets. OBJECTIVES:Our objective is to develop a novel improved cylindrical spinal cord stimulation device that can convert into an optimal geometry once exposed to the body's environment after minimally invasive surgery. Such a device would be able to reduce long-term complications, lead migration, and better cover targeted dermatomes. STUDY DESIGN:Biomaterial selection, medical intervention device design with an in-vitro lab-scale test, and cadaveric experimental study. METHODS:A shape memory alloy nitinol-based cylindrical lead was designed, and its nitinol core material was processed and geometrically programmed for percutaneous insertion into the epidural space and morphing into an optimal geometry once exposed to the body's environment. Deployment of the nitinol component of the design was tested in the lab and human cadaveric models of the epidural space. RESULTS:Deployment of the nitinol component of the proposed cylindrical lead was successfully demonstrated in both a lab model of the epidural space and in the epidural space of a human cadaver in a minimally invasive fashion, indicating that a similar component could be used clinically in a full SCS electrode manufactured in a custom final geometry. LIMITATIONS:The focus of this study was to test the deployment of a novel minimally invasive lead that provides optimal coverage of intended dermatomes using in-vitro methods. Our study does not include in vivo trials. We do not test the electrical components of the design proposed since our design does not make changes to the electrical components of current commercially used cylindrical leads. CONCLUSION:The unique shape memory property of nitinol shows promise in allowing cylindrical spinal cord stimulation leads to expand into a more optimal geometry within the epidural space. By having a body temperature-dependent geometry change, nitinol-based cylindrical leads could reduce lead migration, increase dermatomal coverage, and increase electrode density while maintaining the advantages of minimally invasive insertion.

Thoracic disc herniation and stenosis are relatively rare, and various symptoms make them difficult to diagnose. Due to the complexity of neural and vascular structure, surgical treatment of thoracic pathology is challenging. Endoscopic spine surgery is an emerging minimally invasive surgical option. Based on wide experience on the cervical and lumbar spine, an endoscopic approach for the thoracic pathology can be performed beyond the learning curve. Transforaminal approach for thoracic disc herniation, endoscopic unilateral approach, and bilateral decompression for thoracic stenosis have been reported as favorable and safe surgical options. In the present study, the authors described the detailed surgical procedure as well as tips and tricks.

Endoscopic techniques in spine surgery are rapidly evolving, with operations becoming progressively safer and less invasive. Lumbar interbody fusion (LIF) procedures comprise many spine procedures that have benefited from endoscopic assistance and minimally invasive approaches. Though considerable variation exists within endoscopic LIF, similar principles and techniques are common to all types. Nonetheless, innovations continually emerge, requiring trainees and experienced surgeons to maintain familiarity with the domain and its possibilities. We present two illustrative cases of endoscopic transforaminal lumbar interbody fusion with a comprehensive literature review of the different approaches to endoscopic LIF procedures.

BACKGROUND:Encouraging early time of discharge (TOD) for medical inpatients is commonplace and may potentially improve patient throughput. It is unclear, however, whether early TOD after elective spine surgery achieves this goal without a consequent increase in re-presentations to the hospital. OBJECTIVE:To evaluate whether early TOD results in increased rates of hospital readmission or return to the emergency department after elective anterior cervical spine surgery. METHODS:We analyzed 686 patients who underwent elective uncomplicated anterior cervical spine surgery at a single institution. Logistic regression was used to evaluate the relationship between sociodemographic, procedural, and discharge characteristics, and the outcomes of readmission or return to the emergency department and TOD. RESULTS:In multiple logistic regression, TOD was not associated with increased risk of readmission or return to the emergency department within 30 days of surgery. Weekend discharge (odds ratio [OR] 0.33, 95% CI 0.21-0.53), physical therapy evaluation (OR 0.44, 95% CI 0.28-0.71), and occupational therapy evaluation (OR 0.32, 95% CI 0.17-0.63) were all significantly associated with decreased odds of discharge before noon. Disadvantaged status, as measured by area of deprivation index, was associated with increased odds of readmission or re-presentation (OR 1.86, 95% CI 0.95-3.66), although this result did not achieve statistical significance. CONCLUSION:There does not appear to be an association between readmission or return to the emergency department and early TOD after elective spine surgery. Overuse of inpatient physical and occupational therapy consultations may contribute to decreased patient throughput in surgical admissions.

BACKGROUND:A significant portion of health care spending is driven by a small percentage of the overall population. Understanding risk factors predisposing patients to disproportionate use of health care resources is critical. Our objective was to identify risk factors leading to a prolonged length of stay (LOS) after cervical spine surgery. METHODS:A single-center cohort analysis was performed on patients who underwent elective anterior spine surgery from 2015 to 2021. Multivariate logistic regression evaluated the effects of sociodemographic factors including Area of Deprivation Index (quantifies income, education, employment, and housing quality), procedural, and discharge characteristics on postoperative LOS. Extended LOS was defined as greater than the 90th percentile in midnights for the study population (≥3 midnights). RESULTS:A total of 686 patients were included in the study, with a mean age of 57 years (range, 26-92 years), median of 1 level (1-4) fused, and median LOS of 1 midnight (interquartile range, 1-2). After adjusting for confounders, patients had increased odds of extended LOS if they were highly disadvantaged on the Area of Deprivation Index (odds ratio [OR], 2.24; 95% confidence interval [CI], 1.04-4.82; P = 0.039); had surgery on Thursday or Friday (OR, 1.94; 95% CI, 1.01-3.72; P = 0.046); had a corpectomy performed (OR, 2.81; 95% CI, 1.26-6.28; P = 0.012); or discharged not to home (OR, 8.24; 95% CI, 2.88-23.56; P < 0.001). Patients with extended LOS were more likely to present to the emergency department or be readmitted within 30 days after discharge (P = 0.024). CONCLUSIONS:After adjusting for potential cofounders, patients most disadvantaged on Area of Deprivation Index were more likely to have an extended LOS.

BACKGROUND:Endoscopic spine surgery is associated with less approach trauma than conventional open translaminar surgery. However, objective evidence to corroborate this empiric observation is scarce. Preservation of the anatomic attachment and sensory function of multifidus muscles have been stipulated to be critical to maintaining the normal function of the lumbar spinal motion segment. The authors were interested in comparing the postoperative approach trauma between traditional open translaminar microsurgical and interlaminar endoscopic discectomy. METHODS:The approach trauma to the paraspinal muscles due to interlaminar or open microsurgical discectomy was evaluated on T2-weighted axial magnetic resonance imaging (MRI) images of 39 consecutive patients who underwent lumbar disc surgery. Postoperative MRI images taken at 4 days and within 1 year after surgery were analyzed. Eleven patients underwent conventional open translaminar microdiscectomy surgery. Endoscopic discectomy was performed on 17 patients via the interlaminar and on another 11 patients via the transforaminal approach. The immediate surgical approach trauma was estimated as the defect zone by measuring the normalized relative cross-sectional area (rCSA) of muscle disruption in the surgical corridor 4 days postoperatively. The long-term effect of surgical approach trauma was assessed by measuring the area of the paraspinal muscles that had been replaced by fatty tissue 1 year postoperatively. RESULTS:< 0.001). Fatty replacement of the multifidus muscle was seen on the ipsilateral and contralateral approach side. There was a negligible change in the muscle zone with the transforaminal approach. CONCLUSIONS:Tissue trauma was significantly reduced with endoscopic surgery techniques compared with the traditional translaminar microdiscectomy approach. There was a minor postoperative tissue trauma and hardly any long-term replacement of the multifidus and paraspinal muscles by fatty tissue 1 year postoperatively with the endoscopic technique. The transforaminal approach has the least effect on the paraspinal muscles of the surgical motion segment. Further study is needed to investigate whether these findings translate into decreased postoperative instability or low back pain following endoscopic discectomy surgery. CLINICAL RELEVANCE/CONCLUSIONS:MRI analysis of multifidus atrophy following various lumbar translaminar and transforaminal decompression techniques.

INTRODUCTION:Surgical techniques to treat tumors of the spine often require extensive tissue dissection and bony removal, predisposing patients to elevated risk for perioperative morbidity and mortality. When indicated, minimally invasive surgical techniques may be preferred as they result in less collateral damage and quicker recovery times. Full endoscopic spine surgery (FES) represents an ultra-minimally invasive approach that further minimizes tissue damage. The advantages to the application of FES to treat spinal tumors remain unclear. METHODS:Electronic databases were systematically searched for published literature on the application of FES in spinal oncology to assess its utility, safety, and outcomes via Nurick, McCormick, and Frankel grades, visual analog scale, complication rate, duration of surgery, estimated blood loss, length of stay, and mean follow-up. RESULTS:Fifteen articles describing 72 patients met inclusion criteria. The most common approach was the interlaminar approach (40.98%). The most common spinal level was lumbar (38.89%). The most common goal of surgery was gross total resection (82.11%). The average Nurick grade decreased from 2.96 to 0.67. All patients showed an improvement from Frankel grade C or D to grade E except for one. The average visual analog scale score decreased from 9.3 to 1.3. The complication rate was 6.56%. The average length of stay was 55.2 hours. The average estimated blood loss was 49 mL. The average duration of surgery was 121.26 minutes. The mean follow-up was 10.58 months. CONCLUSION:The utility of FES in spinal oncology is not well understood. Literature results of this technique show promise. Further study is needed to draw definitive conclusions on FES efficacy and safety in spinal oncology.