Faculty Bibliography

BACKGROUND:Optimal approaches for treating surgical spine pathology in very geriatric patients, such as those over the age of 80, remain unclear. OBJECTIVE:To describe outcomes of awake, transforaminal endoscopic surgical treatment for patients 80 years old and older presenting with lumbar radiculopathy. STUDY DESIGN:Retrospective case review. METHODS:The records of 52 consecutive patients who underwent awake transforaminal lumbar endoscopic decompression surgery performed by a single surgeon at a single institution between 2014 and 2019 were retrospectively reviewed. All included patients were followed for at least one year after surgery. RESULTS:Transforaminal surgeries performed were discectomies (21), foraminotomies (7), redo foraminotomies post-laminectomy (5), fusion explorations (13), facet cyst resections (3), spondylolisthesis decompressions (2), and a decompression for metastatic disease (1). Seven patients (13.5%) required repeat surgery at the treated level during the one-year follow-up. For the remaining 45 patients, at one-year follow-up, preoperative visual analog scale (VAS) for leg pain and Oswestry disability index (ODI) improved from 6.9 (± 1.4) and 40.5% (± 11.5) to 1.8 (± 1.4) and 12.0% (± 10.8), respectively. The only complication of the procedure was a single durotomy (2%). LIMITATIONS:Single-center, retrospective case review with a relatively small number of cases with diverse clinical pathology. A multi-center case study with a larger number of patients with a more homogeneous case pathology would be more revealing. CONCLUSIONS:Endoscopic spine surgery offers octogenarians a safe and effective option for the treatment of lumbar degenerative spine disease and may represent a valuable treatment strategy in a growing patient population.

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.

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.

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.

International collaborations can be the key to overcoming innovation implementation hurdles. The authors report on a joint symposium between the International Society For The Advancement of Spine Surgery (ISASS) and La Sociedad Iberolatinoamerica de Columna (SILACO), and La Sociedad Interamericana de Cirurgia de columna de Minima invasión (SICCMII) aimed at improving joint surgeon education programs. The symposium highlighted that patient-related spine care issues are similar across geographical, cultural, and language barriers. The sustainability of such programs depends on funding and mutually respectful relationships orchestrated by multi-lingual leaders who will bridge gaps created by geographical, cultural, and language barriers to effectively develop clinical research content focused on advancing surgeon education and improving patient outcomes across the Americas.

BACKGROUND:Spontaneous spinal cerebrospinal fluid (CSF) leaks are a rare entity that can lead to intracranial hypotension and associated headaches, meningismus, and patient debility. Surgical treatment may be necessary for patients who do not respond to conservative management. Surgical repair of CSF leaks located in the ventral thoracic spine traditionally require an invasive, open approach. METHODS:We describe the case of a patient with a ventral thoracic spontaneous spinal CSF leak associated with a ventral bony osteophyte successfully treated with spinal endoscopy. We also provide a systematic review of the literature to better understand outcomes of this approach. RESULTS:A total of 55 patients were included in the systematic review. The study designs found in the literature review included case reports (66.7%), retrospective cohorts (22.2%), and prospective cohorts (11.1%). Of the studies reporting data, 50% of studies stated they used an open posterior approach to the dural defect, while 37.5% reported using an open anterior approach to the pathology. Only 1 (12.5%) study reported using an endoscope. Most studies (62.5%) used primary closure of the dura in their technique, while 37.5% reported using a local tissue graft (fat or muscle) or a dural sealant for their closure technique, and 25% of studies reported using a dural substitute for their closure technique. Overall mean clinical follow-up was 19.8 months. CONCLUSIONS:The endoscopic approach described here for treatment of this rare entity allows for removal of bony spicules/osteophytes and dural repair without the morbidity associated with traditional open dorsolateral or ventrolateral approaches.