Granulomatous Angiitis of the Central Nervous System Associated with Hodgkin's Lymphoma: Case Report and Literature Review.

Granulomatous angiitis of the central nervous system (GACNS) is a rare cerebrovascular disorder. It usually presents with multifocal neurologic symptoms symptoms including stroke, encephalopathy, and headache. A limited number of case reports describe neurological deficits resulting from GACNS as the manifesting symptoms of Hodgkin's lymphoma (HL). We describe the case of a patient with neurological symptoms from GACNS that led to the diagnosis of HL, as well as a literature review focusing on the association between GACNS and HL.

Intraoperative image-guided spinal navigation: technical pitfalls and their avoidance.

Spinal instrumentation has made significant advances in the last two decades, with transpedicular constructs now widely used in spinal fixation. Pedicle screw constructs are routinely used in thoracolumbar-instrumented fusions, and in recent years, the cervical spine as well. Three-column fixations with pedicle screws provide the most rigid form of posterior stabilization. Surgical landmarks and fluoroscopy have been used routinely for pedicle screw insertion, but a number of studies reveal inaccuracies in placement using these conventional techniques (ranging from 10% to 50%). The ability to combine 3D imaging with intraoperative navigation systems has improved the accuracy and safety of pedicle screw placement, especially in more complex spinal deformities. However, in the authors' experience with image guidance in more than 1500 cases, several potential pitfalls have been identified while using intraoperative spinal navigation that could lead to suboptimal results. This article summarizes the authors' experience with these various pitfalls using spinal navigation, and gives practical tips on their avoidance and management.

Best of both worlds: Use of robotic principles for placing navigated cervical and difficult upper thoracic pedicle screws, a technical nuance.

Navigated pedicle screw placement can be particularly challenging for cervical and upper thoracic levels in obese patients. This technical challenge can be compounded by the smaller diameter tools that can be flexible and therefore confound navigation. It is imperative to avoid excessive manipulation of surrounding tissues to maintain navigation accuracy in the mobile cervical spine.1 Robotic-assisted spinal approaches use firm guides to aid drilling and screw placement but are hindered by high costs with equipment acquisition.2,3 Here, we propose a technical nuance that combines robotic surgical principles with tools that are more readily available in many surgical departments. We present the case of a 64-year-old female with a chief complaint of neck pain, irradiating to the left worse than right arm and prior history of C5-7 anterior cervical discectomy and fusion (ACDF). Imaging showed multi-level degenerative disease and a solid prior C5-7 ACDF with grade I anterolisthesis at C7-T1 due to severe facet degeneration with severe left sided foraminal stenosis. Given failure of conservative management, the patient was brought to the operating room for left C7-T1 foraminotomy and C7-T1 posterior instrumented fusion. Here, we show the use of a tubular retractor fixed to the surgical bed for solid and reproducible trajectory for all of the tools to minimize the risk of surrounding tissue manipulation and its effect on navigation accuracy.

General Versus Nongeneral Anesthesia for Spinal Surgery: A Comparative National Analysis of Reimbursement Trends Over 10 Years.

BACKGROUND AND OBJECTIVES: Nongeneral anesthesia (non-GA) spine surgery is growing in popularity and has facilitated earlier postoperative recovery, reduced cost, and fewer complications compared with spine surgery under general anesthesia (GA). Changes in reimbursement policies have been demonstrated to correlate with clinical practice; however, they have yet to be studied for GA vs non-GA spine procedures. We aimed to investigate trends in physician reimbursement for GA vs non-GA spine surgery in the United States. METHODS: We queried the ACS-NSQIP for GA and non-GA (regional, epidural, spinal, and anesthesia care/intravenous sedation) spine surgeries during 2011-2020. Work relative value units per operative hour (wRVUs/h) were retrieved for decompression or stabilization of the cervical, thoracic, and lumbar spine. Propensity score matching (1:1) was performed using all baseline variables. RESULTS: We included 474 706 patients who underwent spine decompression or stabilization procedures. GA was used in 472 248 operations, whereas 2458 operations were non-GA. The proportion of non-GA spine operations significantly increased during the study period. Operative times ( P < .001) and length of stays ( P < .001) were shorter in non-GA when compared with GA procedures. Non-GA lumbar procedures had significantly higher wRVUs/h when compared with the same procedures performed under GA (decompression; P < .001 and stabilization; P = .039). However, the same could not be said about cervicothoracic procedures. Lumbar decompression surgeries using non-GA witnessed significant yearly increase in wRVUs/h ( P < .01) contrary to GA ( P = .72). Physician reimbursement remained stable for procedures of the cervical or thoracic spine regardless of the anesthesia. CONCLUSION: Non-GA lumbar decompressions and stabilizations are associated with higher and increasing reimbursement trends (wRVUs/h) compared with those under GA. Reimbursement for cervical and thoracic surgeries was equal regardless of the type of anesthesia and being relatively stable during the study period. The adoption of a non-GA technique relative to the GA increased significantly during the study period.

Frailty as a Predictor of Postoperative Morbidity and Mortality in Patients Aged 80 Years and Older Undergoing Instrumented Fusion.

BACKGROUND AND OBJECTIVES: Degenerative spine disease is a leading cause of disability, with increasing prevalence in the older patients. While age has been identified as an independent predictor of outcomes, its predictive value is limited for similar older patients. Here, we aimed to determine the most predictive frailty score of adverse events in patients aged 80 and older undergoing instrumented lumbar fusion. METHODS: We proceeded with a multisite (3 tertiary academic centers) retrospective review including patients undergoing instrumented fusion aged 80 and older from January 2010 to present. A composite end point encompassing 30-day return to operating room, readmission, and mortality was created. We estimated the area under the receiver operating characteristic curve for frailty scores (Modified Frailty Index-5 [MFI-5], Modified Frailty Index-11 [MFI-11], and Charlson Comorbidity Index [CCI]) in relation to that composite score. In addition, we estimated the association between each score and the composite end point by means of logistic regression. RESULTS: A total of 153 patients with an average age of 85 years at the time of surgery were included. We observed a 30-day readmission rate of 11.1%, reoperation of 3.9%, and mortality of 0.6%. The overall rate of the composite end point at 30 days was 25 (15.1%). The AUC for MFI-5 was 0.597 (0.501-0.693), for MFI-11 was 0.620 (0.518-0.723), and for CCI was 0.564 (0.453-0.675). The association between the scores and composite end point did not reach statistical significance for MFI-5 (odds ratio [OR] = 1.45 [0.98-2.15], P = .061) and CCI (OR = 1.13 [0.97-1.31], P = .113) but was statistically significant for MFI-11 (OR = 1.46 [1.07-2.00], P = .018). CONCLUSION: This is the largest study comparing frailty index scores in octogenarians undergoing instrumented lumbar fusion. Our findings suggest that while MFI-11 score correlated with adverse events, the predictive ability of existing scores remains limited, highlighting the need for better approaches to identify select patients at age extremes.

Lumbar Facet Arthroplasty Versus Fusion for Grade-I Degenerative Spondylolisthesis with Stenosis: A Prospective Randomized Controlled Trial.

BACKGROUND: The comparative effectiveness of decompression plus lumbar facet arthroplasty versus decompression plus instrumented lumbar spinal fusion in patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis is unknown. METHODS: In this randomized, controlled, Food and Drug Administration Investigational Device Exemption trial, we assigned patients who had single-level lumbar spinal stenosis and grade-I degenerative spondylolisthesis to undergo decompression plus lumbar facet arthroplasty (arthroplasty group) or decompression plus fusion (fusion group). The primary outcome was a predetermined composite clinical success score. Secondary outcomes included the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg pain, Zurich Claudication Questionnaire (ZCQ), Short Form (SF)-12, radiographic parameters, surgical variables, and complications. RESULTS: A total of 321 adult patients were randomized in a 2:1 fashion, with 219 patients assigned to undergo facet arthroplasty and 102 patients assigned to undergo fusion. Of these, 113 patients (51.6%) in the arthroplasty group and 47 (46.1%) in the fusion group who had either reached 24 months of postoperative follow-up or were deemed early clinical failures were included in the primary outcome analysis. The arthroplasty group had a higher proportion of patients who achieved composite clinical success than did the fusion group (73.5% versus 25.5%; p < 0.001), equating to a between-group difference of 47.9% (95% confidence interval, 33.0% to 62.8%). The arthroplasty group outperformed the fusion group in most patient-reported outcome measures (including the ODI, VAS back pain, and all ZCQ component scores) at 24 months postoperatively. There were no significant differences between groups in surgical variables or complications, except that the fusion group had a higher rate of developing symptomatic adjacent segment degeneration. CONCLUSIONS: Among patients with lumbar spinal stenosis and grade-I degenerative spondylolisthesis, lumbar facet arthroplasty was associated with a higher rate of composite clinical success than fusion was at 24 months postoperatively. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Transient Neuropathic Pain Following Mechanically Assisted Manipulation of the Spine: A Clinical Case Study.

We describe the case of a patient developing acute neuropathic pain in the sciatic nerve distribution following spinal manipulation. Manipulative treatment with an Activator Adjusting Instrument (AAI) was recommended and performed. Within 24 hours, the patient developed severe 10/10 pain originating from the left gluteal area at the site of one of the activator deployments with radiation all the way down his left leg to the foot. He was able to maintain distal left leg strength and sensation. Relief was achieved with subsequent physical therapy techniques to relax his deep gluteal muscles, raising the hypothesis of temporary injury to the deep gluteal muscles, with painful contractions resulting in gluteal region pain as well as sciatic nerve inflammation as the nerve passed through that region. This clinical case illustrates some of the perils and risks of spinal manipulation, particularly in the elderly, and the need for careful patient selection.

Hybrid Minimally Invasive Endoscopic Approach for Gaseous Protrusion Causing L5 Radiculopathy.

We present an illustrative case of a hybrid approach between minimally invasive and endoscopic spine surgery techniques. We utilized this hybrid approach for the first 3 cases to help diminish the learning curve as we started a spinal endoscopy program. The patient is an 85-year-old woman with a prior history of arthrodesis at L3-5. She presented with severe leg pain and imaging evidence of degenerative disk disease with disk protrusion in the extraforaminal zone at L5-S1. Computed tomography imaging shows the disk protrusion to be gaseous in nature. Given failure of conservative management and patient refusal for extension of her prior fusion, she was offered a combined minimally invasive navigated technique and endoscopic approach for far lateral diskectomy. After obtaining the correct trajectory, with confirmation by intraoperative fluoroscopy, microscopic visualization was used to identify the protruded disk and the exiting nerve root (Video 1). Given the difficult visualization, a 30-degree endoscopic probe was used, which enabled real-time visualization of the gaseous protrusion being released in the liquid medium. After decompression, microscopic visualization was used for confirmation, with the patient obtaining a good surgical outcome and complete relief of her presenting pain. This case illustrates the synergism between endoscopic and minimally invasive spine surgery techniques and the unique advantages of enabling visualization of spinal anatomy through a liquid medium with the use of an endoscope.1-3.

A Prospective Study of Lumbar Facet Arthroplasty in the Treatment of Degenerative Spondylolisthesis and Stenosis: Results from the Total Posterior Spine System (TOPS) IDE Study.

STUDY DESIGN: Prospective randomized Food and Drug Administration investigational device exemption clinical trial. OBJECTIVE: The purpose of the present study is to report the 1-year clinical and radiographic outcomes and safety profile of patients who underwent lumbar facet arthroplasty through implantation of the Total Posterior Spine System (TOPS) device. SUMMARY OF BACKGROUND DATA: Lumbar facet arthroplasty is one proposed method of dynamic stabilization to treat grade-1 spondylolisthesis with stenosis; however, there are currently no Food and Drug Administration-approved devices for facet arthroplasty. METHODS: Standard demographic information was collected for each patient. Radiographic parameters and patient-reported outcome measures were assessed preoperatively and at regular postoperative intervals. Complication and reoperation data were also collected for each patient. RESULTS: At the time of this study, 153 patients had undergone implantation of the TOPS device. The mean surgical time was 187.8 minutes and the mean estimated blood loss was 205.7cc. The mean length of hospital stay was 3.0 days. Mean Oswestry Disability Index, Visual Analog Score leg and back, and Zurich Claudication Questionnaire scores improved significantly at all postoperative time points ( P >0.001). There were no clinically significant changes in radiographic parameters, and all operative segments remained mobile at 1-year follow-up. Postoperative complications occurred in 11 patients out of the 153 patients (7.2%) who underwent implantation of the TOPS device. Nine patients (5.9%) underwent a total of 13 reoperations, 1 (0.6%) of which was for device-related failure owing to bilateral L5 pedicle screw loosening. CONCLUSIONS: Lumbar facet arthroplasty with the TOPS device demonstrated a statistically significant improvement in all patient-reported outcome measures and the ability to maintain motion at the index level while limiting sagittal translation with a low complication rate.

Prospective, randomized controlled multicenter study of posterior lumbar facet arthroplasty for the treatment of spondylolisthesis.

OBJECTIVE: The purpose of this study was to evaluate the safety and efficacy of a posterior facet replacement device, the Total Posterior Spine (TOPS) System, for the treatment of one-level symptomatic lumbar stenosis with grade I degenerative spondylolisthesis. Posterior lumbar arthroplasty with facet replacement is a motion-preserving alternative to lumbar decompression and fusion. The authors report the preliminary results from the TOPS FDA investigational device exemption (IDE) trial. METHODS: The study was a prospective, randomized controlled FDA IDE trial comparing the investigational TOPS device with transforaminal lumbar interbody fusion (TLIF) and pedicle screw fixation. The minimum follow-up duration was 24 months. Validated patient-reported outcome measures included the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain. The primary outcome was a composite measure of clinical success: 1) no reoperations, 2) no device breakage, 3) ODI reduction of ≥ 15 points, and 4) no new or worsening neurological deficit. Patients were considered a clinical success only if they met all four measures. Radiographic assessments were made by an independent core laboratory. RESULTS: A total of 249 patients were evaluated (n = 170 in the TOPS group and n = 79 in the TLIF group). There were no statistically significant differences between implanted levels (L4-5: TOPS, 95% and TLIF, 95%) or blood loss. The overall composite measure for clinical success was statistically significantly higher in the TOPS group (85%) compared with the TLIF group (64%) (p = 0.0138). The percentage of patients reporting a minimum 15-point improvement in ODI showed a statistically significant difference (p = 0.037) favoring TOPS (93%) over TLIF (81%). There was no statistically significant difference between groups in the percentage of patients reporting a minimum 20-point improvement on VAS back pain (TOPS, 87%; TLIF, 64%) and leg pain (TOPS, 90%; TLIF, 88%) scores. The rate of surgical reintervention for facet replacement in the TOPS group (5.9%) was lower than the TLIF group (8.8%). The TOPS cohort demonstrated maintenance of flexion/extension range of motion from preoperatively (3.85°) to 24 months (3.86°). CONCLUSIONS: This study demonstrates that posterior lumbar decompression and dynamic stabilization with the TOPS device is safe and efficacious in the treatment of lumbar stenosis with degenerative spondylolisthesis. Additionally, decompression and dynamic stabilization with the TOPS device maintains segmental motion.

A rare anterior spinal epidural cyst mimicking Hirayama disease.

INTRODUCTION: Hirayama disease is a rare focal motor neuron disorder that manifests as slowly progressive unilateral or bilateral hand weakness and atrophy. METHODS: The case report of a young man who presented with the phenotype of Hirayama disease indicated an extensive anterior cervical epidural arachnoid cyst. RESULTS: A 34-year-old man presented with a 5-year history of slowly progressive hand and forearm weakness and atrophy. Nerve conduction studies demonstrated low median and ulnar motor amplitudes, and EMG demonstrated fibrillation potentials and long-duration, high-amplitude motor unit potentials in C6-T4-innervated muscles. MRI demonstrated a longitudinally extensive anterior spinal epidural cyst extending from C2 to L1. The patient had improved hand strength after surgery. CONCLUSIONS: Anterior cervical epidural spinal cysts should be considered in the differential diagnosis in patients who present with slowly progressive hand weakness.

Myelopathy after traumatic lumbar vertebral intraosseous arteriovenous fistula with epidural venous drainage treated with transvenous embolization.

Spinal epidural arteriovenous fistulas are an uncommon entity. The authors present an interesting case of a 48-year-old man involved in a MVC five months prior to presenting with bilateral lower extremity weakness and hypoesthesia below the knees. MRI demonstrated a flow void in the L1 vertebral body burst fracture along with a dilated basivertebral vein draining in to engorged epidural venous plexus. Angiography confirmed an intraosseous arteriovenous fistula fed by T12 and L1arteries and epidural venous drainage. Complete obliteration by arterial embolization was precluded by origin of the artery of Adamkiewicz from the feeding L1 lumbar artery. Embolization using a transvenous approach allowed for successful obliteration of the fistula. Following the procedure, the patient had significant immediate improvement in the lower extremity symptoms. This is the first report of a posttraumatic spinal epidural arteriovenous fistula secondary to a vertebral burst fracture successfully treated by transvenous embolization.

Load sharing and stabilization effects of anterior cervical devices.

STUDY DESIGN: Biomechanical human cadaveric cervical flexibility testing with direct load-sharing measurement. OBJECTIVE: To determine if the flexibility and load-sharing characteristics of a functional spinal unit were affected by anterior treatments for cervical pathologies. SUMMARY OF BACKGROUND DATA: With advancements in polymers, anterior cervical plates have used thermoplastics including recent designs from biodegradable polylactide acids. However, the difference in material properties between metal and polymer can be significant. METHODS: Thirteen cervical spine specimens were subjected to 5 treatments at C4-C5. Each treatment for each specimen was subjected to multidirectional flexibility testing. The third cycle was used for treatment comparisons. RESULTS: With the integrated load cell spacer, the mean range of motion for the functional spinal unit measured on average 104% + or - 40% normalized to the intact control. The mean biodegradable and titanium plate were 55% + or - 31% and 40% + or - 36%, respectively. Both plates exhibited statistically lower mean range of motions (P = 0.001 and P < 0.001) compared with spacers. The load transmitted through the interbody space was 54% + or - 20%, 43% + or - 20%, and 33% + or - 15% on average for the spacer, biodegradable, and titanium plate constructs, respectively. No statistically significant difference was detected between the biodegradable plate and spacer (P = 0.214). CONCLUSIONS: From this research, a biodegradable plate offers immediate postoperative stability significantly different than spacer alone treatments but with graft load sharing that is statistically no different. Thus, the intrinsic lower native material modulus of elasticity of biodegradable polymers has biomechanical implications. However, clinical evidence, particularly for long-term outcomes, will be required in understanding the efficacy of biodegradable polymers.

Minimally invasive approach to extraforaminal disc herniations at the lumbosacral junction using an operating microscope: case series and review of the literature.

Surgical access to extraforaminal lumbar disc herniations is complicated due to the unique anatomical constraints of the region. Minimizing complications during microdiscectomies at the level of L5-S1 in particular remains a challenge. The authors report on a small series of patients and provide a video presentation of a minimally invasive approach to L5-S1 extraforaminal lumbar disc herniations utilizing a tubular retractor with microscopic visualization.

Augmented reality for the surgeon: Systematic review.

INTRODUCTION: Since the introduction of wearable head-up displays, there has been much interest in the surgical community adapting this technology into routine surgical practice. METHODS: We used the keywords augmented reality OR wearable device OR head-up display AND surgery using PubMed, EBSCO, IEEE and SCOPUS databases. After exclusions, 74 published articles that evaluated the utility of wearable head-up displays in surgical settings were included in our review. RESULTS: Across all studies, the most common use of head-up displays was in cases of live streaming from surgical microscopes, navigation, monitoring of vital signs, and display of preoperative images. The most commonly used head-up display was Google Glass. Head-up displays enhanced surgeons' operating experience; common disadvantages include limited battery life, display size and discomfort. CONCLUSIONS: Due to ergonomic issues with dual-screen devices, augmented reality devices with the capacity to overlay images onto the surgical field will be key features of next-generation surgical head-up displays.

Technical feasibility and safety of an intraoperative head-up display device during spine instrumentation.

BACKGROUND: The primary aim of this study was to determine the safety and feasibility of capturing and streaming neuronavigation images onto a head-up display during spine instrumentation. METHODS: Using a novel device, neuronavigation images were captured and transferred wirelessly via a password-encrypted network to the head-up display. At the end of the procedure, the surgeons completed a survey to gather their opinions of the system. RESULTS: Forty pedicle screws were placed using the head-up display. The average screw placement time was slightly shorter when the head-up display was used (4.13 min with vs. 4.86 min without). The post-procedure survey demonstrated that 79% of surgeon's responses were positive. CONCLUSION: A wearable head-up display can benefit current neuronavigation systems, but larger, outcomes-based trials are needed. Higher processing speed would allow streaming of higher resolution images. Along with an enlarged display, these may significantly improve utilization of this technology. Copyright © 2016 John Wiley & Sons, Ltd.

Redirecting pedicle screws: a revision spinal fusion strategy using three-dimensional image guidance.

BACKGROUND: Pedicle screws are a preferred method for spinal fixation because of their three-column support and rigid posterior stabilization. The purpose of this study was to evaluate the outcome of patients requiring pedicle screw redirection, and to describe a technique using cone-beam computed tomography (cbCT). METHODS: A retrospective review of 30 patients undergoing revision spinal fusion with redirection of pedicle screws was performed. Fifty pedicle screws were redirected in these patients using cbCT-based 3D image guidance. They were graded pre- and post-operatively using an established grading system. RESULTS: No complications occurred in this study as a result of redirection. No pedicle breach was noted in all of the redirected pedicle screws. CONCLUSION: Redirection of misplaced pedicle screws using cbCT-based 3D image guidance seems to be safe and accurate in our experience. Further studies are needed to establish its safety, accuracy, fusion rate, and clinical outcome compared with other methods. Copyright © 2016 John Wiley & Sons, Ltd.

Radiographic comparison of cross-sectional lumbar pedicle fill when placing screws with navigation versus free-hand technique.

BACKGROUND: Pedicle screws are often used for spinal fixation. Increasing the percentage of pedicle that is filled with the screw presumably yields greater fixation. It has not been shown whether spinal navigation helps surgeons more completely fill their instrumented pedicles. METHODS: Fifty consecutive patients from each arm (navigated and free-hand) were retrospectively reviewed. The cross-sectional area of each instrumented lumbar pedicle and screw were measured using an automatic area calculation tool. The coronal images and measurements were blinded to the surgeons. RESULTS: The instrumented pedicles in the navigated patients were significantly more filled by screws than the pedicles in the non-navigated patients (P < 0.001). CONCLUSION: Obtaining a higher cross-sectional percentage fill of the pedicle with a screw is expected to provide greater spinal fixation in instrumented fusion surgery. This study shows that utilizing spinal navigation helps to more completely fill the pedicles that are being instrumented. Copyright © 2015 John Wiley & Sons, Ltd.

Biomechanics of transvertebral screw fixation in the thoracic spine: an in vitro study.

OBJECTIVE Transvertebral screws provide stability in thoracic spinal fixation surgeries, with their use mainly limited to patients who require a pedicle screw salvage technique. However, the biomechanical impact of transvertebral screws alone, when they are inserted across 2 vertebral bodies, has not been studied. In this study, the authors assessed the stability offered by a transvertebral screw construct for posterior instrumentation and compared its biomechanical performance to that of standard bilateral pedicle screw and rod (PSR) fixation. METHODS Fourteen fresh human cadaveric thoracic spine segments from T-6 to T-11 were divided into 2 groups with similar ages and bone quality. Group 1 received transvertebral screws across 2 levels without rods and subsequently with interconnecting bilateral rods at 3 levels (T8-10). Group 2 received bilateral PSR fixation and were sequentially tested with interconnecting rods at T7-8 and T9-10, at T8-9, and at T8-10. Flexibility tests were performed on intact and instrumented specimens in both groups. Presurgical and postsurgical O-arm 3D images were obtained to verify screw placement. RESULTS The mean range of motion (ROM) per motion segment with transvertebral screws spanning 2 levels compared with the intact condition was 66% of the mean intact ROM during flexion-extension (p = 0.013), 69% during lateral bending (p = 0.015), and 47% during axial rotation (p < 0.001). The mean ROM per motion segment with PSR spanning 2 levels compared with the intact condition was 38% of the mean intact ROM during flexion-extension (p < 0.001), 57% during lateral bending (p = 0.007), and 27% during axial rotation (p < 0.001). Adding bilateral rods to the 3 levels with transvertebral screws decreased the mean ROM per motion segment to 28% of intact ROM during flexion-extension (p < 0.001), 37% during lateral bending (p < 0.001), and 30% during axial rotation (p < 0.001). The mean ROM per motion segment for PSR spanning 3 levels was 21% of intact ROM during flexion-extension (p < 0.001), 33% during lateral bending (p < 0.001), and 22% during axial rotation (p < 0.001). CONCLUSIONS Biomechanically, fixation with a novel technique in the thoracic spine involving transvertebral screws showed restoration of stability to well within the stability provided by PSR fixation.

A case series on the technical use of three-dimensional image guidance in subaxial anterior cervical surgery.

BACKGROUND: Three dimensional (3D) image guidance has been used to improve the safety of complex spine surgeries, but its use has been limited in anterior cervical spine approaches. METHODS: Twenty-two patients underwent complex anterior cervical spine surgeries in which 3D image guidance provided intraoperative assistance with the dissection, decompression and implant placement. One of two paired systems, the BrainLAB (BrainLAB, Westchester, Illinois) system, or Stealth (Medtronic Inc., Littleton, Massachusetts) system was used for 3D image guidance in this study. RESULTS: Image guidance was able to reliably locate pertinent anatomical structures in complex anterior cervical spine surgery involving re-exploration, dissection around vertebral arteries or deformity correction. No complications occurred, and no patients required a revision anterior surgery. CONCLUSION: This technical note describes the setup and technique for the use of cone beam computed tomography (cbCT)-based, 3D image guidance in subaxial anterior cervical surgery. The authors have found this technique to be a useful adjunct in revision anterior cervical procedures, as well as anterior cervical procedures involving corpectomy or tumor removal.