Modern Spine Surgery Research Articles

Demineralized Bone Matrix and Fibers in Spinal Fusion.

Formation of bony fusion after arthrodesis depends on osteoinduction, osteoconduction, and osteogenesis. Traditionally, the patient's own bone, or autograft, has been used to provide biological material necessary for these steps. However, the amount of autograft obtainable is often inadequate. Modern spine surgery has adopted the use of many autograft extenders or replacements, such as demineralized bone matrix or fibers. The present article covers the history of bone grafting, the production and technical details of demineralized bone matrix, and the evidence supporting its use in spine fusions.

A Century of Evolution in Spine Surgery Publications: A Bibliometric Analysis of the Field From 1900 to 2023.

Spine surgery has advanced in concert with our deeper understanding of its elements. Narrowly focused bibliometric analyses have been conducted previously, but never on the entire corpus of the field. Using big data and bibliometrics, we appraised the entire corpus of spine surgery publications to study the evolution of the specialty as a scholarly field since 1900. We queried Web of Science for all contents from 13 major publications dedicated to spine surgery. We next queried by topic [topic = (spine OR spinal OR vertebrae OR vertebral OR intervertebral OR disc OR disk)]; these results were filtered to include articles published by 49 other publications that were manually determined to contain pertinent articles. Articles, along with their metadata, were exported. Statistical and bibliometric analyses were performed using the Bibliometrix R package and various Python packages. Eighty-five thousand five hundred articles from 62 journals and 134 707 unique authors were identified. The annual growth rate of publications was 2.78%, with a surge after 1980, concurrent with the growth of specialized journals. International coauthorship, absent before 1970, increased exponentially with the formation of influential spine study groups. Reference publication year spectroscopy allowed us to identify 200 articles that comprise the historical roots of modern spine surgery and each of its subdisciplines. We mapped the emergence of new topics and saw a recent lexical evolution toward outcomes- and patient-centric terms. Female and minority coauthorship has increased since 1990, but remains low, and disparities across major publications persist. The field of spine surgery was borne from pioneering individuals who published their findings in a variety of journals. The renaissance of spine surgery has been powered by international collaboration and is increasingly outcomes focused. While spine surgery is gradually becoming more diverse, there is a clear need for further promotion and outreach to under-represented populations.

Essential Surgical Techniques During Fully Endoscopic Spine Surgery: A Historical Review and Future Perspectives

Full-endoscopic spine surgery (FESS) offers minimally invasive techniques for treating spinal lesions with smaller incisions, leading to reduced tissue damage and consequently more rapid patient recovery. The essential techniques in FESS —namely, the transforaminal and interlaminar approaches—have evolved with technological advances in endoscopic systems and surgeon expertise. The transforaminal approach consists of “inside-out” and “outside-in” techniques that have distinct applications depending on the patient’s condition. The interlaminar approach, similar to traditional spinal surgery techniques, is gaining wider acceptance due to its efficacy in addressing unique anatomical challenges. Advanced procedures, such as endoscopic laminectomy and interbody fusion surgery, coupled with navigation systems, have broadened the scope of endoscopic spine surgery, making it an increasingly vital tool in modern spinal surgery.

Full endoscopic spine surgery

BackgroundWith a dramatic increase in elderly population worldwide, the prevalence of degenerative spine disease is steadily rising. Even though the entire spinal column is affected the problem is more commonly seen in the lumbar, cervical spine and to some extent the thoracic spine. The treatment of symptomatic lumbar disc or stenosis is primarily conservative with analgesics, epidural steroids and physiotherapy. Surgery is advised only if conservative treatment is ineffective. Conventional open microscopic procedures even though are still a gold standard, have the disadvantages of excessive muscle damage and bone resection, epidural scarring along with prolonged hospital stay and increased need of postoperative analgesics. Minimal access spine surgeries minimize surgical access related injury by minimizing soft tissue and muscle damage and also bony resection thus preventing iatrogenic instability and unnecessary fusions. This leads to good functional preservation of the spine and enhances early postoperative recovery and early return to work. Full endoscopic spine surgeries are one of the more sophisticated and advanced form of MIS surgeries. PurposeFull endoscopy has definitive benefits over conventional microsurgical techniques. These include better and clear vision of the pathology due to presence of irrigation fluid channel, minimal soft tissue and bone trauma, better and relatively easy approach to deep seated pathologies like thoracic disc herniations and a possibility to avoid fusion surgeries. The purpose of this article is to describe these benefits, give an overview of the two main approaches - transforaminal and interlaminar, their indications, contraindications and their limitations. The article also describes about the challenges in overcoming the learning curve and its future prospectives. ConclusionFull endoscopic spine surgery is one of the fastest growing technique in the field of modern spine surgery. Better intraoperative visualization of the pathology, lesser incidence of complications, faster recovery time, less postoperative pain, better relief of symptoms and early return to activity are the main reasons behind this rapid growth. With better patient outcomes and reduced medical costs, the procedure is going to be more accepted, relevant and popular procedure in future.

Proximal Junctional Kyphosis in Modern Spine Surgery: Why Is it So Common?

In the past few decades, proximal junctional kyphosis (PJK) has emerged as a new complication after instrumented spinal fusion in adult and pediatric spinal deformities. This phenomenon has occurred concomitantly with the rise of robust instrumentation techniques and enhancement of our abilities to obtain greater spinal deformity correction. The goal of this paper is to review the mechanical and biological causes of PJK and recommend prevention strategies.

Longitudinal Assessment of Modern Spine Surgery Training: 10-Year Follow-up of a Nationwide Survey of Residency and Spine Fellowship Program Directors.

This study is a cross-sectional survey distributed to all PDs of ORTH and NSGY residencies and spine fellowships in the United States. Participants were queried regarding characteristics of their program, ideal characteristics of residency training, and opinions regarding the current training environment. χ2 tests were used to compare answers over the years. In total, 241 PDs completed the survey. From 2013 to 2023, NSGY increased the proportion of residents with >300 spine cases (86%-100%) while ORTH remained with >90% of residents with < 225 cases (p < 0.05). A greater number of NSGY PDs encouraged spine fellowship even for community spine surgery practice (0% in 2013 vs. 14% in 2023, p < 0.05), which continued to be significantly different from ORTH PDs (∼88% agreed, p > 0.05). 100% of NSGY PDs remained confident in their residents performing spine surgery, whereas ORTH confidence significantly decreased from 43% in 2013 to 25% in 2023 (p < 0.05). For spinal deformity, orthopaedic PDs (92%), NSGY PDs (96%), and fellowship directors (95%), all agreed that a spine fellowship should be pursued (p = 0.99). In both 2013 and 2023, approximately 44% were satisfied with the spine training model in the United States. In 2013, 24% of all PDs believed we should have a dedicated spine residency, which increased to 39% in 2023 (fellowship: 57%, ORTH: 38%, NSGY: 21%) (p < 0.05). Spine surgery training continues to evolve, yet ORTH and neurological surgery training remains significantly different in case volumes and educational strengths. In both 2013 and 2023, less than 50% of PDs were satisfied with the current spine surgery training model, and a growing minority believe that spine surgery should have its own residency training pathway. IV.

Opioid use after elective spine surgery: Do spine surgery patients consume less than prescribed today?

BackgroundThe opioid epidemic in the US has led prescribers to reevaluate postoperative pain control particularly in the field of spine surgery, where postoperative analgesia requirements and consumption have historically been high. There is a need to mitigate the quantity of unused pills after surgery by adjusting prescribing practices. Achieving the balance of pain control after surgery without overprescribing opioids may be accomplished by developing a modified approach to prescribing practices; however, there is a need to first understand the opioid requirements of the modern spine surgery patient with respect to their elective spine surgery. Therefore, the primary aim of this study was to determine the percentage of opioids not utilized at 90-days after elective spine surgery. Secondary aims were to identify differences in the percentage of unused opioids between surgical subgroups and preoperative opioid status, to determine factors associated with opioid utilization, and to estimate the distribution of opioids consumed to control pain up to the 90th percentile in each surgical subgroup. MethodsIn this prospective, observational cohort study, adults undergoing elective spine surgery at a multi-surgeon, single center were prospectively enrolled and divided into subgroups: anterior cervical, lumbar decompression, and short-segment lumbar fusion. Prescribed MMEs were identified from prescriptions, consumed MMEs were obtained from pill counts, and the percent leftover was calculated. Distributions of MMEs consumed were analyzed to compare utilization between preoperative opioid users or non-users within each surgical subgroup. ResultsOf 117 patients, 41.9% were preoperative opioid users. The percentage of unused opioids by surgical subgroup was: 45.4% cervical, 57.3% lumbar decompression, and 37.4% lumbar fusion (p=0.066). The percentage of unused opioids by preoperative opioid exposure was greater in the opioid non-users (58.0%) than users (28.4%, p<0.001)). Regression analysis showed that surgical subgroup and preoperative opioid exposure were associated with leftover opioids. ConclusionsAt 90-days, the percentage of unused opioids was over 45% in this cohort of elective spine surgery patients and was nearly double in the group without preoperative opioid exposure. These results suggest the modern elective spine surgery patient is using less opioids than prescribed, supporting the conclusion that the number of MMEs prescribed can be reduced to minimize quantities of leftover pills available for diversion, without sacrificing the priority of appropriate postoperative pain control.

Three-dimensional High-definition Exoscope in Minimally Invasive Transforaminal Lumbar Interbody Fusion: A Retrospective Cohort Study.

The operative microscope (OM) has revolutionized the field of modern spine surgery, however, it remains limited by several drawbacks. Recently, the exoscope (EX) system has been designed to assistant spine surgery. It provides a three-dimensional (3D) high-definition (HD) operative experience and becomes an alternative to the OM. The aim of the study was to evaluate the clinical outcomes, advantages and limitations of EX-assisted minimally invasive transforaminal lumbar interbody fusion (EMIS-TLIF) and OM-assisted MIS-TLIF (OMIS-TLIF). The clinical outcomes were assessed in 47 patients with lumbar degenerative diseases (LDD) who underwent MIS-TLIF assisted with the OM or EX between January 2019 and September 2020. A total of 22 were treated with EMIS-TLIF, and 25 received OMIS-TLIF. Perioperative parameters (including sex, age, number of fusion levels and body mass index), perioperative parameters (operation time, intraoperative blood loss, postoperative drainage, postoperative hospitalization stay, and duration of follow-up), visual analogue scale (VAS) of back pain, VAS of leg pain, Oswestry disability index (ODI) scores and clinical outcomes were assessed and compared. Image quality, handling of equipment, ergonomics, 3D glasses and educational usefulness were scored according to a questionnaire. Operation time in the OMIS-TLIF group (121.92 ± 16.92 min) was significantly increased compared with that in the EMIS-TLIF group (111.00 ± 19.87 min) (P < 0.05). The VAS of the back pain and ODI scores in the EMIS-TLIF group were significantly lower compared with the OMIS-TLIF group at 1 week postoperatively (P < 0.05). The good-excellent outcomes rate was 90.91% in the EMIS-TLIF group and 88.00% in the OMIS-TLIF group, and there was no significant difference. A total of 44 visits completed the questionnaire. The results of the questionnaire showed that the EX has exhibited advantages regarding handing of equipment, ergonomics and educational usefulness, and comparable image quality as compared with the OM, however, operating surgeons complained uncomfortable sensation when wearing 3D glasses. The EMIS-TLIF was a safe and effective procedure in the management of LDD as compared with the OMIS-LIF. Meanwhile, EMIS-TLIF might resulted in a short operation time.

Simulation Training in Spine Surgery.

Simulated surgery is part of a growing paradigm shift in surgical education as a whole. Various modalities from cadaver models to virtual reality have been developed and studied within the context of surgical education. Simulation training in spine surgery has an immense potential to improve education and ultimately improve patient safety. This is due to the inherent risk of operating the spine and the technical difficulty of modern techniques. Common procedures in the modern orthopaedic armamentarium, such as pedicle screw placement, can be simulated, and proficiency is rapidly achieved before application in patients. Furthermore, complications such as dural tears can be simulated and effectively managed in a safe environment with simulation. New techniques with steeper learning curves, such as minimally invasive techniques, can now be safely simulated. Hence, augmenting surgical education through simulation has great potential to benefit trainees and practicing orthopaedic surgeons in modern spine surgery techniques. Additional work will aim to improve access to such technologies and integrate them into the current orthopaedic training curriculum.

Three-dimensional high-definition exoscope (Kestrel View II) in anterior cervical discectomy and fusion: a valid alternative to operative microscope-assisted surgery

Operative microscope (OM) has greatly advanced modern spine surgery, but remains limited by several drawbacks. Therefore, a three-dimensional (3D) high-definition (HD) exoscope (EX) (Kestrel View II, Mataka Kohli, Japan) system has been developed and used as an alternative to the OM. The aim of this study was to assess and compare the perioperative data and clinical outcomes of anterior cervical discectomy and fusion (ACDF) procedure with either an EX or OM. Forty-eight patients with cervical spondylotic myelopathy (CSM) underwent ACDF assisted by the EX or OM between January 2019 and December 2019. We collected and compared data on operative time, intraoperative bleeding, postoperative hospitalization stay, complications, and clinical outcomes between the two groups. The clinical outcomes were evaluated by using visual analogue scale (VAS) scores, Japanese Orthopedic Association (JOA) scores, the recovery rate of JOA scores, and Odom criteria. The operative time in the EX group was significantly shorter than that in the OM group (P < 0.05). The VAS and JOA scores were significantly improved in both groups after surgery (P < 0.05). In addition, the VAS scores in the EX group were significantly lower than those in the OM group at 1week postoperatively (P < 0.05). The good-to-excellent outcome rates were 90.48 and 88.89% in the EX group and OM group, respectively, whereas the complication occurrence rates of the EX group and OM group were 4.76 and 11.11%, respectively. EX-assisted and OM-assisted ACDF resulted in similar clinical outcomes for CSM, while EX-assisted surgery may be related to a short operative time and fewer complications.

The effectiveness of spatially cross-linked polymer in the postoperative epidural fibrosis prevention: an experimental study

Introduction. Epidural fibrosis is an urgent problem in modern spinal surgery and orthopedics. The formation of connective tissue in the epidural space after performing surgical interventions on the spinal column inevitably leads to adhesion of the latter to the dura mater and compression of neural structures, followed by the formation of clinical and neurological symptoms. The search for literary sources in domestic and foreign scientific databases has demonstrated the presence of several works studying the effectiveness of barrier methods for preventing the development of epidural fibrosis. It should be noted that the results of these studies are ambiguous and largely contradictory.The purpose was to study the effectiveness of using a spatially cross-linked polymer in the postoperative lumbar epidural fibrosis prevention in an experiment.Materials and methods. The study included 26 male Wistar rats (average body weight 338.5±9.07 g), which were divided into two groups: Group I (control, n = 12): animals underwent laminectomy at the level of vertebral bodies LVII – SI without application of spatially crosslinked polymer; Group II (experimental, n = 14): animals underwent laminectomy at the level of vertebral bodies LVII – SI followed by application of a spatially cross-linked polymer to the dura mater. The morphological and instrumental parameters were studied.Results. Significant differences were noted in the severity of epidural fibrosis (χ2 = 14.846, p = 0.003), the number of newly formed vessels (F = 14.371, p&lt;0.001), the number of fibroblasts (F = 11.158, p&lt;0.001), as well as in the severity of vertebral stenosis channe l according to multislice computed tomography (χ2 = 17.207, p=0.002) between the control and experimental groups of animals.Conclusion. Application of a spatially cross-linked polymer to the dura mater is an effective way to prevent the development of postoperative epidural fibrosis.

The impact of robot-assisted spine surgeries on clinical outcomes: A systemic review and meta-analysis.

Medical robotics has enabled a significant advancement in the field of modern spine surgery, especially in pedicle screw fixation. A plethora of studies focused on the accuracy of pedicle fixation in robotic-assisted (RA) technology. However, it is not clear whether RA techniques can improve patients' clinical outcomes. We retrieved relevant studies that compare the differences between RA and freehand (FH) techniques in spine surgeries from the following databases: PubMed, Embase, Cochrane Library and Web of Science. The perioperative outcomes of this technology were measured with parameters including radiation exposure, operative time, the length of hospital stay, complication rates and revision rates. Two reviewers independently reviewed the studies in our sample, assessed their validity and extracted relevant data. Our search resulted in a sample of 23 eligible studies, which involved 1247 patients (5042 pedicle screws) in the RA group and 1273 patients (4830 pedicle screws) in the FH group. With regard to the radiation exposure, the fluoroscopy time was less in surgeries assisted by Mazor robots (standard mean difference [SMD] = -0.96, 95% CI = -1.60 to -0.31) but more in Tianji robots (SMD = 0.91, 95% CI = 0.17 to 1.66) and ROSA robots (SMD = 2.57, 95% CI = 2.01 to 3.13). For radiation dose, a decrease was observed in Tianji robots (SMD = -1.59, 95% CI = -2.13 to -1.05). In the lumbar subgroup, the use of robots increased the operative time (SMD = 0.53, 95% CI = 0.19 to 0.86). In the degenerative diseases (DG) group, there was a significant decrease in the length of hospital stay when robots were introduced (SMD = -0.30, 95% CI = -0.48 to -0.12). While in the DF (deformity) and DG group, a significant increase was found (SMD = 0.17, 95% CI = 0.02 to 0.32). The complication (OR = 0.41, 95% CI = 0.26 to 0.66) and the revision rates (OR = 0.38, 95% CI = 0.24 to 0.60) showed a significant decrease in the RA group compared to the conventional FH group. This study suggests that RA spine surgeries would result in fewer complications, a lower revision rate and shorter length of hospital stay. As the technology continues to evolve, we may expect more applications of robotic systems in spine surgeries.

Safety and accuracy of robot-assisted placement of pedicle screws compared to conventional free-hand technique: a systematic review and meta-analysis

BACKGROUND CONTEXTThe introduction and integration of robot technology into modern spine surgery provides surgeons with millimeter accuracy for pedicle screw placement. Coupled with computer-based navigation platforms, robot-assisted spine surgery utilizes augmented reality to potentially improve the safety profile of instrumentation. PURPOSEIn this study, the authors seek to determine the safety and efficacy of robotic-assisted pedicle screw placement compared to conventional free-hand (FH) technique. STUDY DESIGN/SETTINGWe conducted a systematic review of the electronic databases using different MeSH terms from 1980 to 2020. OUTCOME MEASURESThe present study measures pedicle screw accuracy, complication rates, proximal-facet joint violation, intraoperative radiation time, radiation dosage, and length of surgery. RESULTSA total of 1,525 patients (7,379 pedicle screws) from 19 studies with 777 patients (51.0% with 3,684 pedicle screws) in the robotic-assisted group were included. Perfect pedicle screw accuracy, as categorized by Gerztbein-Robbin Grade A, was significantly superior with robotic-assisted surgery compared to FH-technique (Odds ratio [OR]: 1.68, 95% confidence interval [CI]: 1.20–2.35; p=.003). Similarly, clinically acceptable pedicle screw accuracy (Grade A+B) was significantly higher with robotic-assisted surgery versus FH-technique (OR: 1.54, 95% CI: 1.01–2.37; p=.05). Furthermore, the complication rates and proximal-facet joint violation were 69% (OR: 0.31, 95% CI: 0.20–0.48; p<.00001) and 92% less likely (OR: 0.08, 95% CI: 0.03–0.20; p<.00001) with robotic-assisted surgery versus FH-group. Robotic-assisted pedicle screw implantation significantly reduced intraoperative radiation time (MD: −5.30, 95% CI: −6.83–3.76; p<.00001) and radiation dosage (MD: −3.70, 95% CI: −4.80–2.60; p<.00001) compared to the conventional FH-group. However, the length of surgery was significantly higher with robotic-assisted surgery (MD: 22.70, 95% CI: 6.57–38.83; p=.006) compared to the FH-group. CONCLUSIONThis meta-analysis corroborates the accuracy of robot-assisted pedicle screw placement.

Intraoperative navigation: Current applications and future directions

This article will describe and characterize the variety of navigation options available to the spine surgeon and how they contribute to modern spine surgery. Current products generally involve preoperative 3D imaging, registration of the patient's anatomy in the operating room, intraoperative 3D visualization, and active stereotactic instrument guidance. Current navigation technology focuses most on accurate pedicle screw placement, but is showing increasing promise for guiding precise osseous resections. As technology improves alongside surgeon familiarity and lowering costs, future applications of this technology for decompression and instrumentation of spinal elements could offer substantial benefits and ultimately produce superior outcomes over traditional techniques.

Research on the predicting power of the revised Tokuhashi system: how much time can surgery give to patients with short life expectancy?

ObjectThe primary treatment option for symptomatic metastatic spinal tumors is surgery. Prognostic systems are designed to assist in the establishment of the indication and the choice of surgical methodology. The best-known prognostic system is the revised Tokuhashi system, which has a predictive ability of about 60%. In our study, we are attempting to find the reason for its poor predictive ability, despite its proper separation ability.MethodsWe have designed a one-center-based retrospective clinical trial, by which we would like to test the feasibility and the inaccuracy of the revised Tokuhashi system. In our database, there are 329 patients who underwent surgery. Statistical analysis was performed.ResultsA significant increase in survival time was observed in the ‘conservative’ category. Earlier studies reported OS 0.15 at the 180-day control time, in contrast with our 0.38 OS value. The literature suggested supportive care for this category, but in our population, every patient underwent surgery. Our population passes the 0.15 OS value on day 475. We propose an adjustment of the Tokuhashi category scores. We observed significant success in resolving pain. Motor functions were improved or stabilized compared to changes in vegetative dysfunction.ConclusionAccording to our results, the Tokuhashi scoring system makes very conservative predictions and prefers non-surgical palliative or supportive care. Surgical treatment increases the life expectancy of patients in poor condition. We propose modifying the therapeutic options of the revised Tokuhashi system, taking into consideration modern spine surgery techniques.

Robotics in spinal surgery.

Although the da Vinci robot system has garnered much attention in the realm of surgery over the past few decades, several new surgical robotic systems have been developed for spinal surgery with varying levels of robot autonomy and surgeon-specified input. These devices are currently being considered as potential avenues for increasing the precision of any surgical intervention. The following review will attempt to provide an overview of robotics in modern spine surgery and how these devices will continue to be employed in various sectors across the field.

TOMOGRAPHIC STUDY OF THE S2-ALAR-ILIAC SCREW TECHNIQUE IN BRAZILIAN MEN

ABSTRACT Objective The use of pedicle screws was a milestone for modern spinal surgery. This type of fixation, due to its superior biomechanics, gave greater fixation power, greater capacity to withstand the pulling forces and, therefore, greater stability and lower rates of pseudoarthrosis. Fixation of the lumbosacral junction, even with the development of these new implants, remains a challenge mainly because the considerable rates of pseudoarthrosis. The use of iliac screws solves the biomechanical difficulties. However, its use shows high rates of surgical wound problems. The S2-Alar-Iliac screw (S2AI) came as a solution to these complications. The lack of studies about anatomical and anthropometric parameters in the Brazilian population justifies the study. Methods Eleven hip tomographies of Brazilian adult males were analyzed by four evaluators. The right and left sides were considered. In each patient, measurements were made of greater and shorter bone length, greater and smaller bone diameter, distance from the entry point to the skin, sagittal and axial angles related to the hypothetical insertion of an S2AI screw and compared to the same measurements obtained with the iliac screw. Results The mean bone length was 136.7 mm, the greatest bone diameter was 24.8 mm, the smallest bone diameter was 19.7 mm and the distance from the screw to the skin was 42.1 mm for the S2AI screw. Conclusions The obtained data present an average of the sample that can be useful in the decision of the surgical technique in the studied group. Level of evidence I; Diagnostic Studies (Anatomical Investigation).

A retrospective review of modern spine surgery in the skeletal dysplasia population

Searchable abstracts of presentations at key conferences on calcified tissues ISSN 2052-1219 (online)

Mismatch between rod bending and actual post-operative lordosis in short lumbar arthrodesis with poly axial screws

Restoring sagittal balance is a common goal in modern spine surgery (Le Huec and Roussouly 2011). To do so, the adequate lordosis need to be restored between the fused vertebrae. In degenerative po...

Fluoroscopic Cranial Radiation Exposure in Spine Surgery: A Prospective Single-Center Evaluation in Operating Room Personnel.

Cranial radiation exposure during instrumented spine surgery is not well documented. We set out to measure this risk to the patient, surgeon, surgical resident, and scrub technician during these procedures. Forty-seven individuals were enrolled during a 1.5-year period between October 2014 and March 2016 at the University of New Mexico Department of Neurosurgery. Radiation doses were obtained through electronic dosimeters placed on the surgical cap over the temporal scalp (bilaterally on surgeon and resident assist, unilaterally on surgical scrub on the side facing radiation source) and on the midline of the patient's exposed cranium. Of the 47 procedures, 39 (83%) were open and 8 (17%) were minimally invasive or percutaneous instrumented procedures. A total of 91 motion segments were treated, with a mean of 1.9 levels per case (57% lumbosacral, 34% cervical, and 2.1% thoracic). Total fluoroscopic time was 12.9 minutes. Mean dose per case (mrem/case) was calculated for the spine surgeon (1.4), resident assist (1.4), surgical scrub (1.2), and the patient (3.6). All doses were within federal safety guidelines. A spine surgeon would need to perform more than 1400 cases per year to reach the current federal maximum permissible dose for head exposure. There was no difference in cranial radiation exposure between operating room staff during spine surgeries. Moreover, the doses measured at the cranium were within national safety limits. Current protective technologies have significantly reduced the amount of ionizing radiation exposure during routine spine procedures; however, changes in behavior or equipment may further reduce radiation exposure to health care workers. Radiation exposure to patients and hospital staff remains a major concern in the practice of modern spine surgery. Cranial exposure remains the only established environmental risk factor for brain tumors, such as gliomas and meningiomas. Our study shows that all those exposed to radiation during spine surgery had cranial doses well within the national safety limits.