Fijación lumbar posterior empleando el sistema de imagen quirúrgica O-arm: experiencia inicial

ObjectThe use of transpedicular screw fixation has been widely accepted for the treatment of degenerative and traumatic pathology of the lumbar spine. Complications of spinal instrumentation can be serious. Screw misplacement can result in unintended durotomy, nerve root and/or cauda equina injury. In comparison to fluoroscopy-assisted screw placement, computer-assisted image guidance has been shown to achieve overall higher rates of accuracy. The O-arm is able to obtain computed tomography (CT)-type images with multiplanar reconstruction. In this study we evaluated a cohort of patients who underwent posterior lumbar fusion with pedicle screws utilizing the O-arm imaging system.MethodsA retrospective review of 40 consecutive patients who underwent posterior lumbar fusion surgery with O-arm utilization, was performed. The study population included 14 males and 26 females. Age range was 39-85 years with an average of 63.8 years. Twenty one patients had degenerative lumbar stenosis (52.5%) and 19 had spondylolisthesis (47.5%). Intraoperative CT-images were obtained. The mean time for surgery and screw placement was assessed.ResultsA total of 252 pedicle screws were sited using O-arm navigation system, with a mean of 6.3 screws per patient (range 4-10). On the basis of intraoperative CT, 3 screws were redirected, representing a 98.81% accuracy rate.The mean duration of surgery was 157.2 (90-240) minutes and the mean time for screw placement was 7.13 (3.08-15) minutes per screw.Three patients (7.5%) developed superficial wound infections which were treated conservatively. No patients required a return to the operating room because of screw malposition.ConclusionThe use of intraoperative O-arm imaging system with computer-assisted navigation significantly increases the surgical accuracy and safety of pedicle screw placement in lumbar fusion surgery.     

Intraoperative computed tomography-guided navigation versus fluoroscopy for single-position surgery after lateral lumbar interbody fusion

There are no reports comparing fluoroscopy and intraoperative computed tomography (CT) navigation in lateral single-position surgery (SPS) in terms of surgical outcomes or implant-related complications. Therefore, the purpose of this study was to use radiological evaluation to compare the incidence of instrument-related complications in SPS of lateral lumbar interbody fusion (LLIF) using fluoroscopy with that using CT navigation techniques. We evaluated 99 patients who underwent lateral SPS. Twenty-six patients had a percutaneous pedicle screw (PPS) inserted under fluoroscopy (SPS-C group), and 73 patients had a PPS inserted under intraoperative CT navigation (SPS-O group). Average operation time was shorter in the SPS-C group than in the SPS-O group (88.4 ± 24.4 min versus 111.9 ± 35.3 min, respectively, P = 0.003). However, there was no significant difference between the two groups in postoperative thigh symptoms or reoperation rate. The screw insertion angle of the SPS-C group was smaller than that of the SPS-O group, but there was no significant difference in the rate of screw misplacement (4.6% versus 3.4%, respectively, P = 0.556). By contrast, facet joint violation (FJV) was significantly lower in the SPS-O group than in the SPS-C group (8.4% versus 21.3%, respectively, P < 0.001). While fluoroscopy was superior to intraoperative CT navigation in terms of mean surgery time, there was no significant difference in the accuracy of PPS insertion between fluoroscopy and intraoperative CT navigation. The advantage of intraoperative CT navigation over fluoroscopy is that it significantly decreases the occurrence of FJV in SPS.     

True accuracy of percutaneous pedicle screw placement in thoracic and lumbar spinal fixation with a CT-based navigation system: Intraoperative and postoperative assessment of 763 percutaneous pedicle screws

PurposeTo investigate intraoperative reinsertion of percutaneous pedicle screw (PPS) with intraoperative CT-based navigation and to evaluate the rate of deviation of PPS at postoperative radiographic examination.MethodsSeven hundred sixty-three screws were inserted in 138 patients. We investigated the rate of occurrence of intraoperative PPS reinsertion after the diagnosis of screw deviation by fluoroscopy and the causes of each screw deviation. The subsequent distribution of PPS deviation was evaluated by postoperative CT. We also assess the difference in variance between the group judged to be PPS misplaced intra-/postoperatively (IOD group/POD group) and appropriate PPS placement (ND group).ResultsAmong all the screws inserted, 10 (1.3%) were diagnosed as being deviated by fluoroscopy during surgery, and 74 (9.7%) screws were found to be deviated at postoperative CT evaluation. We found more pedicle screw mismatch in the POD group than in the ND group (52.7 vs 11.0%, P < 0.001). The distance between the screw and the reference was greater in the IOD group than that in the ND group (1.4 ± 1.2 vs 2.4 ± 1.1 vertebral levels, P = 0.016). In one patient in the IOD group, a motor function deficit was observed postoperatively.ConclusionPPS fixation under intraoperative CT-based navigation did not prevent screw deviation completely. It is necessary to consider errors that occur during surgery and to confirm placement with real-time assistance such as fluoroscopy even in a surgery performed under CT navigation assistance.     

Evaluation of the implantation of transpedicular screws in spinal instrumentation with free-hand technique and navigation-assisted with intraoperative computed tomography: An analytical-positional study

BackgroundSpinal instrumentation using transpedicular screws has been used for decades to stabilize the spine. In October 2018, an intraoperative CT system was acquired in the Neurosurgery service of the University Hospital Complex of Vigo, this being the first model of these characteristics in the Spanish Public Health System, so we began a study from January 2015 to December 2019 to assess the precision of the transpedicular screws implanted with this system compared with a control group performed with the classical technique and final fluoroscopic control.MethodsThe study was carried out in patients who required transpedicular instrumentation surgery, in total 655 screws were placed, 339 using the free-hand technique (Group A) and 316 assisted with intraoperative CT navigation (Group B) (p > 0.05). Demographic characteristics, related to surgery and the screw implantation grades were assessed using the Gertzbein–Robbins classification.Results92 patients were evaluated, between 12 and 86 years (average: 57.1 years). 161 thoracic screws (24.6%) and 494 lumbo-sacral screws (75.4%) were implanted. Of the thoracic screws, 33 produced a pedicle rupture. For the lumbo-sacral screws, 71 have had pedicle violation. The overall correct positioning rate for the free-hand group was 72.6% and for the CT group it was 96.5% (p < 0.05).ConclusionThe accuracy rate is higher in thoracic-lumbar instrumentation in the navigation group versus free-hand group with fluoroscopic control.     

New generation intraoperative three-dimensional imaging (O-arm) in 100 spine surgeries: Does it change the surgical procedure?

The O-arm (Medtronic Sofamor Danek, Inc., Memphis, TN, USA), an intraoperative CT scan imaging system, may provide high-quality imaging information to the surgeon. To our knowledge, its impact on spine surgery has not been studied. We reviewed 100 consecutive spine surgical procedures which utilized the new generation mobile intraoperative CT imaging system (O-arm). The most common diagnoses were degenerative conditions (disk disease, spondylolisthesis, stenosis and acquired kyphosis), seen in 49 patients. The most common indication for imaging was spinal instrumentation in 81 patients (74 utilized pedicle screws). In 52 (70%) of these, the O-arm was used to assess screw position after placement; in 22 (30%), it was coupled with Stealth navigation (Medtronic Sofamor Danek, Inc.) to guide screw placement. Another indication was to assess adequacy of spinal decompression in 38 patients; in 19 (50%) of these, intrathecal contrast material was used to obtain an intraoperative CT myelogram. In 20 patients O-arm findings led to direct surgeon intervention in the form of screw removal/repositioning (n = 13), further decompression (n = 6), interbody spacer repositioning (n = 1), and removal of kyphoplasty trocar (n = 1). In 20% of spine surgeries, the procedure was changed based on O-arm imaging findings. We found the O-arm to be useful for assessment of instrumentation position, adequacy of spinal decompression, and confirmation of balloon containment and cement filling in kyphoplasty. When used with navigation for image-guided surgery, it obviated the need for registration.     

Fluoroscopic versus CT-guided cortical bone trajectory pedicle screw fixation: Comparing trajectory related complications

Cortical bone trajectory (CBT) pedicle screw fixation is an emerging technique for treatment of degenerative spine disease which requires either intraoperative fluoroscopy or intraoperative CT guidance (iCT). To date, there has been no direct comparison of these two navigation modalities; here we compare fluoroscopic versus iCT navigation for CBT pedicle screw fixation. We retrospectively reviewed all patients who underwent CBT screw fixation with either fluoroscopic or iCT guidance for lumbar degenerative disease by the senior author. Trajectory-related complications such as medial or lateral breach were compared on postoperative CT, in addition to the incidence of trajectory-related dural tear. We also compared general surgical complications such as postoperative infection and decompression related durotomies. Thirty-eight patients (19 fluoroscopic, 19 CT-guided) who underwent placement of 182 cortical screws (88 fluoroscopic, 94 CT-guided) were identified. In terms of trajectory-related complications, the iCT cohort had fewer medial breaches (1/94) compared to the fluoroscopic cohort (6/88) (p = 0.05). Each group had one lateral breach (p = 0.73). There was one case of CSF leak from screw placement in the fluoroscopic cohort, but none in the iCT cohort (p = 0.48). Overall, there were eight trajectory-related complications in the fluoroscopic cohort versus two in the iCT cohort (p = 0.04). Our data suggests statistically significant decreased trajectory-related complications with iCT-guided CBT screw fixation as compared to fluoroscopically guided. In terms of general surgical complications, while we observed increased postoperative infections in our fluoroscopic cohort, there was no statistically significant difference.     

Clinical and radiological Comparison of treatment of atlantoaxial instability by posterior C1–C2 transarticular screw fixation or C1 lateral mass-C2 pedicle screw fixation

We compared the clinical and radiological results of posterior atlantoaxial fixation surgery using transarticular screws to those using a polyaxial screw–rod system in 55 patients with symptomatic atlantoaxial instability. Patients underwent posterior C1–C2 fixation: 28 patients (group 1) underwent C1–C2 transarticular screw fixation and 27 patients (group 2) underwent C1 lateral mass–C2 pedicle screw fixation. Patients were followed-up for at least 24 months. The clinical and radiological results were evaluated in the early postoperative period and at 3, 6, 12 and 24 months after surgery. Long-term postoperative stability and bone fusion were examined. After surgery, 93% of patients in group 1 and 96% of patients in group 2 were free of neck pain. The solid fusion rates were 82% for group 1 patients and 96% for group 2 patients at 12 months (p < 0.092). In group 1, three patients showed fibrous union. Four patients had hardware failure due to a screw malposition (one in group 1) and pseudoarthrodesis (two in group 1 and one in group 2). One patient in group 1 had cerebrospinal fluid leakage. One patient in group 2 had occipital neuralgia. One vertebral artery injury occurred during the screw placement in group 1 and another in group 2 during the muscle dissection. C1–C2 transarticular screw fixation and C1 lateral mass–C2 pedicle screw fixation both produced excellent results for stabilization of the atlantoaxial complex, but the radiological outcome tended to be superior in C1 lateral mass–C2 pedicle screw fixation.     

Application of different thresholds for instrumentation device testing in minimally invasive lumbosacral spine fixation

The main aim of this study was evaluating the reliability of stimulus-evoked electromyography (using different thresholds for stimulation of the instrumentation devices) for minimally invasive pedicle screw placement in the lumbosacral spine. A threshold of 5 mA was applied for the pedicle access needle. 7 mA was applied for the tapscrew and pedicle screw stimulation. The existence of threshold differences between vertebral levels was also assessed. All patients underwent postoperative computed tomography (CT) to determine the accuracy of pedicle screw placement. A total of 172 percutaneous pedicle screws were placed in 52 patients. 94.1% of screws were placed at L4, L5 and S1 vertebral levels. No statistically significant differences existed in thresholds of the pedicle access needles, tapscrews and pedicle screws between vertebral levels. In four instances, the pedicle access needle stimulation had a threshold of 5 mA (no breaches were associated). In the rest of occasions, the pedicle access needles had stimulation thresholds above 5 mA. In all instances, tapscrew and pedicle screw thresholds were above 7 mA; the tapscrews and pedicle screws had significantly greater thresholds than the pedicle access needles. No statistically significant differences existed in thresholds between tapscrews and pedicle screws. Postoperative CT imaging revealed one lateral pedicle violation. Both breach rate and false negative rate were 0.5%. No false positive cases were observed. No patients experienced postoperative pedicle screw–related neurologic deficits. A threshold of 5 mA for the pedicle access needle stimulation seems to be safe. Greater than 7 mA should be used for the tapscrew and pedicle screw stimulation.     

O-Arm-based image guidance in minimally invasive spine surgery: Technical note

Three-dimensional (3D) image guidance technology is gaining popularity in spine surgery. The O-Arm navigation platform, which relies on cone-beam CT images acquired in the operative position, represents the most recent advancement in this field. We report our technique for MIS pedicle screw insertion using the O-Arm system and present two illustrative cases. We used percutaneous technique for short construct cases and “transfascial” technique for long-construct cases. O-Arm based navigation in minimally invasive spine surgery is safe and feasible. This technology may improve surgical accuracy and clinical outcomes but long term prospective studies are needed to validate this.     

Atornillado anterior de la odontoides empleando tomografía computarizada de haz cónico intraoperatorio y navegación

ObjectiveThe purpose of this study was to asses the value of intraoperative cone-beam CT (O-arm) and stereotactic navigation for the insertion of anterior odontoid screws.Materials and methodsthis was a retrospective review of patients receiving surgical treatment for traumatic odontoid fractures during a period of 18 months.Procedures were guided with O-arm assistance in all cases. The screw position was verified with an intraoperative CT scan. Intraoperative and clinical parameters were evaluated. Odontoid fracture fusion was assessed on postoperative CT scans obtained at 3 and 6 months’ follow-upResultsFive patients were included in this series; 4 patients (80%) were male. Mean age was 63.6 years (range 35-83 years). All fractures were acute type ii odontoid fractures. The mean operative time was 116 minutes (range 60-160 minutes). Successful screw placement, judged by intraoperative computed tomography, was attained in all 5 patients (100%). The average preoperative and postoperative times were 8.6 (range 2-22 days) and 4.2 days (range 3-7 days) respectively. No neurological deterioration occurred after surgery. The rate of bone fusion was 80% (4/5).ConclusionAlthough this initial study evaluated a small number of patients, anterior odontoid screw fixation utilizing the O-arm appears to be safe and accurate. This system allows immediate CT imaging in the operating room to verify screw position.     

Significance of Preoperative Prone Position Computed Tomography in Free Hand Subaxial Cervical Pedicular Screwing

ObjectiveThe subaxial cervical pedicle screwing technique shows powerful biomechanical properties for posterior cervical fusion. When applying a pedicle screw using the freehand technique, it is essential to analyse cervical computed tomography and plan the surgery accordingly. Normal cervical computed tomography is usually performed in the supine position, whereas during surgery, the patient lies in a prone position. This fact leads us to suppose that radiological evaluations may yield misleading results. Our study aimed to investigate whether there is any superiority between preoperative preparation on computed tomography performed in the prone position and that performed in the supine position. MethodsThis study included 17 patients (132 pedicle screws) who were recently operated on with cervical vertebral computed tomography in the prone position and 17 patients (136 pedicle screws) who were operated on by conventional cervical vertebral computed tomography as the control group. The patients in both groups were compared in terms of age, gender, pathological diagnosis, screw malposition and complications. A screw malposition evaluation was made according to the Gertzbein-Robbins scale. ResultsNo statistically significant difference was observed between the two groups regarding age, gender and pathological diagnosis. The screw malposition rate (from 11.1% to 6.9%, p<0.05), mean malposition distance (from 2.18 mm to 1.86 mm, p <0.05), and complications statistically significantly decreased in the prone position computed tomography group. ConclusionPreoperative surgical planning by performing cervical vertebral computed tomography in the prone position reduces screw malposition and complications. Our surgical success increased with a simple modification that can be applied by all clinicians without creating additional radiation exposure or additional costs.     

Intra-operative cone-beam CT (O-arm) and stereotactic navigation in acute spinal trauma surgery

The purpose of this ambispective cohort study is to describe the emerging role of intra-operative cone-beam CT (O-arm®, Medtronic, Minneapolis, MN, USA), frequently coupled with stereotactic navigation (StealthStation®, Medtronic), in the surgical management of acute spinal trauma. All patients with acute spinal trauma between May 2009 and May 2011 who were treated with the use of the O-arm were identified from a prospectively collected spine database and retrospectively analyzed to characterize indications and outcomes. Over the two-year period, the O-arm was used in 183 spinal operations; 27 of these (15%) involved acute spinal trauma. Within the trauma cohort, 14 injuries were in the cervical spine, nine at the cervicothoracic junction, and four were in the thoracolumbar spine. In 12 patients (44%) pre-existing aberrant and challenging anatomy, commonly ankylosing conditions, were present. Surgical techniques included transarticular atlantoaxial fixation and direct osteosynthesis of a Hangman’s fracture performed entirely percutaneously (via two stab incisions) using O-arm assisted stereotactic navigation. No trauma cases using O-arm assisted navigation had iatrogenic neurovascular injury and none required subsequent revision surgery for implant malposition, compared with a revision rate of 1.2% of patients with non-navigated acute spinal trauma during the same interval. Technical factors associated with successful application of this technology in the setting of acute spinal trauma were detailed. O-arm assisted navigation can overcome anatomical challenges and broaden the available stabilization options in the management of acute spinal trauma. Other advantages include protecting the surgical team from cumulative fluoroscopic radiation exposure and patients from repeat surgery due to implant malposition.     

Routine spinal navigation for thoraco–lumbar pedicle screw insertion using the O-arm three-dimensional imaging system improves placement accuracy

Modern image-guided spinal navigation employs high-quality intra-operative three dimensional (3D) images to improve the accuracy of spinal surgery. This study aimed to assess the accuracy of thoraco-lumbar pedicle screw insertion using the O-arm (Breakaway Imaging, LLC, Littleton, MA, USA) 3D imaging system. Ninety-two patients underwent insertion of thoraco–lumbar pedicle screws guided by O-arm navigation over a 27 month period. Intra-operative scans were retrospectively reviewed for pedicle breach. The operative time of patients where O-arm navigation was used was compared to a matched control group where fluoroscopy was used. A total of 467 pedicle screws were inserted. Four hundred and forty-five screws (95.3%) were placed within the pedicle without any breach (Gertzbein classification grade 0). Sixteen screws (3.4%) had a pedicle breach of less than 2 mm (Gertzbein classification grade 1), and six screws (1.3%) had a pedicle breach between 2 mm and 4 mm (Gertzbein classification grade 2). The grade 2 screws were revised intra-operatively. There was no incidence of neurovascular injury in this series of patients. The mean operative time for O-arm patients was 5.25 hours. In a matched control group of fluoroscopy patients, the mean operative time was 4.75 hours. The difference in the mean operative time between the two groups was not statistically significant (p = 0.15, paired t-test). Stereotactic navigation based on intra-operative O-arm 3D imaging resulted in high accuracy in thoraco–lumbar pedicle screw insertion.     

三维虚拟图像导航技术在脊柱椎弓根螺钉固定中的应用☆

背景：近年来经椎弓根螺钉固定技术显著提高了脊柱固定强度和融合效率,但是椎弓根螺钉置入位置不佳可能损害脊髓和神经引起严重并发症。 目的：评估置入前CT扫描三维虚拟图像导航技术在脊柱椎弓根螺钉固定中的应用价值。 设计、时间及地点：前瞻性、随机对照观察,于2006-01/2008-12在中国医学科学院北京协和医院骨科完成。 对象：纳入因脊柱疾病行椎弓根螺钉固定的患者95例,导航组45例,常规组50例。 方法：将95例患者按随机数字表法分为2组,导航组术中在计算机导航技术辅助下置入椎弓根螺钉,常规组采用传统的解剖标志法结合术中透视定位置入椎弓根螺钉。 主要观察指标：比较2组间螺钉钉道准备时间、螺钉位置优良率及螺钉置入后并发症的发生率。 结果：导航组中36例患者共置入椎弓根螺钉206枚,优良率96.1%;有9例患者因故未能行导航。常规组50例患者共置入椎弓根螺钉285枚,优良率100.0%,无位置差的螺钉。2组患者的螺钉位置优良率差异无显著性意义(P > 0.05)。导航组的钉道准备时间显著长于常规组[(360±22),(56±8) s,P < 0.01]。2组患者螺钉置入后均无并发症发生。 结论：与传统解剖标志定位法相比,应用置入前CT扫描三维虚拟图像导航技术置入椎弓根螺钉的精度无明显差异,且延长了手术时间,其在脊柱椎弓根螺钉固定中的应用价值有限。     

Intraoperative neurophysiological monitoring (IONM): lessons learned from 32 case events in 2069 spine cases

Intraoperative neurophysiological monitoring (IONM) is becoming the standard of care for many spinal surgeries, especially those with deformity correction and instrumentation. We reviewed 2069 spine cases with multimodality IONM including somatosensory evoked potentials (SSEP), transcranial electrical motor evoked potentials (TCeMEP), and spontaneous and triggered electromyography (s-EMG and t-EMG) in a University setting over a period of four years to examine perioperative clinical findings when an IONM event was noted and to ascertain how IONM has affected our ability to avoid potential neurological injury during spine surgery. We performed a retrospective analysis of cases from 2006 to 2010 to study the frequency and cause of intraoperative events detected via IONM and the clinical outcome of the patient. There were 32 cases (1.5%) with possible intraoperative events. There were 17 (53%) cases where IONM changes affected the course of the surgery and prevented possible postoperative neurological deficits. Seven cases (41%) were due to deformity correction, five (29%) due to hypotension, four (24%) due to patient positioning, and one (6%) due to a screw requiring repositioning. None of the 17 patients had postoperative motor or sensory deficits. There were four cases with false-positive IONM findings due to correctible technical issues. Three cases required surgical revision due to pedicle screw malposition. In each case, s-EMGs failed to exhibit intraoperative changes but the patient presented with postoperative radiculopathy. We believe that the use of t-EMGs may have prevented these complications. This review reinforces the importance of multimodality IONM for spinal surgery. The incidence of possible events in our series was 1.5%, and several likely postoperative neurologic deficits were avoided by intraoperative intervention.     

术中CT辅助下椎弓根螺钉置入的精确性和安全性评估

目的 评估术中CT辅助下椎弓根固定技术的安全性和准确性。方法 回顾性分析2014年5月至2015年5月术中CT辅助下椎弓根固定手术治疗的39例脊柱脊髓疾病患者的临床资料,其中脊柱脊髓损伤6例,颅颈交界区畸形6例,脊柱退行性变14例,脊柱脊髓肿瘤13例;术后应用Gertzbein-Robbins分级评价螺钉植入的精确性。结果 椎弓根螺钉固定总数为112枚,术中根据CT影像进行位置修正的螺钉共38枚;其中脊柱脊髓损伤23枚,颅颈交界区畸形8枚,脊柱退行性变40枚,脊柱脊髓肿瘤41枚;颈椎 23枚,胸椎48枚,腰椎41枚。根据Gertzbein-Robbins分级0级105枚,1级5枚,2级2枚。术后发生切口感染4例、脑脊液漏2例、神经损伤1例,未发生与螺钉植入直接相关的并发症,也无二次翻修病例。结论 术中CT能够帮助术者在术中发现位置不良的椎弓根螺钉并对其进行修正,提高椎弓根螺钉植入固定术的精确性和安全性。     

First case report using optical topographic-guided navigation in revision spinal fusion for calcified thoracic disk

Computer assisted navigation systems are frequently used in spine surgery to improve the accuracy of pedicle screw placement. The 7D Surgical System utilizes optical topographic imaging (OTI) with a camera positioned directly above the surgical field to perform rapid registration from a pre-operative CT scan onto anatomical landmarks with zero intra-operative radiation exposure. This current technology requires an open approach with well-exposed bony anatomy, raising concerns about using the 7D Surgical System in revision surgery, where typical anatomical landmarks may be altered, missing, or obscured by prior hardware. To overcome this, the 7D Surgical System is capable of registering off prior hardware. Here, we present the first published report of 7D Surgical System’s registration off prior hardware in a revision spinal fusion. The registration was accurate, and the workflow was easy and efficient with one registration required for 3 levels of instrumentation and discectomy/corpectomy. This demonstrates that the 7D Surgical System can be used in revision cases with altered, missing, or obscured anatomy.     

Effect of intraoperative navigation on operative time in 1-level lumbar fusion surgery

The use of intraoperative image guided navigation (NAV) in spine surgery is increasing. NAV is purported to improve the accuracy of pedicle screw placement but has been criticized for potentially increasing surgical cost, a component of which may be prolongation of total operative time due to time required for setup and intra-operative imaging and registration. In this study, we examine the effect of the introduction of O-Arm conical CT spinal navigation on surgical duration. We retrospectively analyzed consecutive freehand (FH) (n = 63) and NAV (n = 70) 1-level lumbar transpedicular instrumentation cases at a single institution by a single surgeon. We recorded setup and procedure time for each case. NAV was associated with significantly shorter total operative time for 1-level lumbar fusions compared to FH (4:30 +/− 0:42 hours vs. 4:53 +/− 0:39 hours, p = 0.0013). This shortening of total operative time was realized despite a trend toward slightly longer setup times with NAV. We also found a significant decrease in operative length over time in NAV but not FH cases, indicative of a “learning curve” associated with NAV. The use of NAV in 1-level lumbar transpedicular instrumentation surgery is associated with significantly shorter total operative time compared to the FH technique, and its efficiency improves over time. These data should factor into cost-effectiveness analyses of the use of NAV for these cases.     

Early complications after instrumentation of the lumbar spine using cortical bone trajectory technique

This retrospective chart review aimed to identify and report on a series of early complications that resulted from instrumentation of the lumbar spine using the cortical bone trajectory (CBT) technique. CBT technique is a novel method for fixation of the lumbar spine. Since it was first described in 2009 this technique has gained significant popularity. Here we report a series of early complications that have developed in patients who had lumbar spine fusion using the CBT technique. A retrospective chart review was performed in which all cases utilizing the CBT technique for instrumentation of the lumbar spine by two fellowship trained spine surgeons at our institution between July 2012 and May 2014 were reviewed. Medical records were reviewed to determine the number of patients who went on to develop an early complication after instrumentation with this technique. An early complication was defined as any of the following occurring within 3 months of surgery: (1) early screw loosening confirmed by post-operative CT scan, (2) evidence of fracture development confirmed by post-operative CT scan, (3) intra-operatively identified durotomy, (4) superficial or deep post-operative infection and (5) neurological injury. A total of 22 cases using the CBT technique were performed in our department. Of these cases two patients went onto develop early screw loosening, one developed an intra-operative pars fracture, one developed a dural tear and lastly, one patient developed both a pedicle fracture and early screw loosening. At our institution a total of five patients thus far have developed early complications after undergoing instrumentation of the lumbar spine using the CBT technique between 2012–2014.     

3D-Slicer联合sina软件辅助椎弓根置钉在椎管内肿瘤手术中的应用

目的 探讨3D-Slicer联合sina软件辅助椎弓根置钉技术在椎管内肿瘤手术中的应用效果。方法 回顾性分析2018年1月至2021年1月手术治疗的46例椎管内肿瘤的临床资料。术中应用3D-Slicer联合sina软件辅助定位置钉26例（观察组）,徒手定位置钉20例（对照组）。术后行C臂、CT扫描,按照Gertzbein-Robbins方法评估置钉的准确性。结果 观察组术中射线量、单钉置入时间、术中出血量、术后术区引流量、术后住院时间均明显低于对照组（P<0.05）。观察组置钉穿破皮质骨发生率（16.38%）、不良置钉率（5.17%）、术中调整置钉率（18.10%）明显低于对照组（分别31.11%、13.33%、37.78%;P<0.05）。两组血管神经损伤及术后1年内钉棒相关并发症发生率均无统计学差异（P>0.05）。结论 与徒手定位置钉相比,3D-Slicer联合sina软件辅助椎弓根置钉,明显提高置钉的准确性,并具减少手术相关的副损伤,缩短住院时间。