Navigated placement of iliac bolts: description of a new technique

Management of C0 Sacral Fractures Based on the AO Spine Sacral Injury Classification: A Narrative Review

The Arbeitsgemeinschaft fur Osteosynthese fragen Spine Sacral Injury Classification hierarchically separates fractures based on their injury severity with A-type fractures representing less severe injuries and C-type fractures representing the most severe fracture types. C0 fractures represent moderately severe injuries and have historically been referred to as nondisplaced "U-type" fractures. Injury management of these fractures can be controversial. Therefore, the purpose of this narrative review is to first discuss the Arbeitsgemeinschaft fur Osteosynthese fragen Spine Sacral Injury Classification System and describe the different fracture types and classification modifiers, with particular emphasis on C0 fracture types. The narrative review will then focus on the epidemiology and etiology of C0 fractures with subsequent discussion focused on the clinical presentation for patients with these injuries. Next, we will describe the imaging findings associated with these injuries and discuss the injury management of these injuries with particular emphasis on operative management. Finally, we will outline the outcomes and complications that can be expected during the treatment of these injuries.

The impact of misplaced percutaneous iliac dynamic reference frame pins used during navigated spine surgery: incidence and outcomes

OBJECTIVE

Image guidance requires placement of a dynamic reference frame (DRF), often either onto local spinous process or by freehand intraosseous DRF placement into the ilium via the posterior superior iliac spine (PSIS). There is a paucity of studies in the literature that describe the complications of intraosseous DRF placement. The aim of this study was to describe the radiographic location, prevalence and nature of complications, and long-term clinical outcomes of attempted DRF placement into the PSIS.

METHODS

All lumbosacral spine surgical procedures performed between August 2019 and February 2021 at a single institution were queried, and operations in which a DRF was targeted to the PSIS were included. Patient demographic characteristics, indications for surgery, surgical outcomes, and complications were extracted. Intraoperative CT scans were reviewed by 2 independent researchers to determine the accuracy of DRF placement into the PSIS and to assess for DRF malposition.

RESULTS

Of 497 lumbar spine operations performed between August 2019 and February 2021 by 4 surgeons, 85 utilized intraoperative navigation with a PSIS pin. Thirteen operations were excluded due to an inability to visualize the entirety of the pin on intraoperative CT. Of 72 DRFs evaluated, 77.8% had been correctly placed in the PSIS. Of the 22.2% of DRFs not placed into the PSIS, 11 entered the sacrum, 6 crossed the sacroiliac joint, and 2 were deep enough to enter the pelvis. Pain at the pin site was present in 4 patients, of whom 3 had resolution of pain at the last follow-up evaluation. There were no significant complications due to DRF placement: no sacral fractures, significant navigation errors, retroperitoneal hematomas, or neurological deficits. Over a mean ± SD follow-up period of 9 ± 5.2 months, there were no incidences of pin site infection. Interrater reliability between the reviewers was 95.8%.

CONCLUSIONS

This was the first study to examine radiological and clinical outcomes after DRF placement in the PSIS. In this study, a majority of pins were correctly placed within the PSIS, although 22.2% of pins were malpositioned. There were no serious complications, and a majority of those patients with persistent pin site pain had resolution at last follow-up.

Application of 3-dimensional printing guide template and pointed lotus-style regulator in percutaneous pedicle screw fixation for thoracolumbar fractures

This study aims to analysis the efficacy of the 3D printing percutaneous guide template in combination with the pointed lotus-style regulator in percutaneous pedicle screw fixation. 60 thoracolumbar fractures patients receiving percutaneous pedicle screw fixation (PPSF) were enrolled and randomly divided into 3 groups. Patients in Group A received traditional PPSF, while patients in Group B received PPSF with flat end lotus-style regulator and patients in Group C received PPSF with pointed lotus-style regulator. The experimental results showed that the highest number of pedicle screw successfully inserted by the first time was in group C, while lowest in group A (P < 0.05). The total time of fluoroscopy and operation were lower in group C, and higher in group A (P < 0.05). VAS and ODI scores were all lower after surgery than before surgery in 3groups. VAS and ODI scores were lower in group B and C, compared with group A at day 1, 7 after surgery (P < 0.05). KA decreased significantly in 3 groups after surgery and no difference in KA change between 3 groups (P > 0.05). Taken together, Application of the 3D printing guide template in combination with pointed lotus-style regulator improved the accuracy of pedicle insertion.

Trial registration: ClinicalTrials.gov Identifier: NCT04980131. Registered 18/07/2021.

Robotic navigation in spine surgery: Where are we now and where are we going?

Robotic navigation is a new and rapidly emerging niche within minimally invasive spine surgery. The robotic arms-race began in 2004 and has resulted in no less than four major robotic surgical adjuncts. Current Food and Drug Administration (FDA)-approved applications of robotic navigation are limited to pedicle screw instrumentation, but new indications and experimental applications are rapidly emerging. As with any new technology, robotic navigation must be vetted for clinical efficacy, efficiency, safety, and cost-effectiveness. Given the rapid advancements made on a yearly basis, it is important to make frequent and objective assessments of the available technology. Thus, the authors seek to provide the most up-to-date review of the history, currently available technology, learning curve, novel applications, and cost effectiveness of today's available robotic systems as it relates to spine surgery.

The Clinical Impact of Image Guidance and Robotics in Spinal Surgery: A Review of Safety, Accuracy, Efficiency, and Complication Reduction

Image guidance (IG) and robotic-assisted (RA) surgery are modern technological advancements that have provided novel ways to perform precise and accurate spinal surgery. These innovations supply real-time, three-dimensional imaging information to aid in instrumentation, decompression, and implant placement. Although nothing can replace the knowledge and expertise of an experienced spine surgeon, these platforms do have the potential to supplement the individual surgeon's capabilities. Specific advantages include more precise pedicle screw placement, minimally invasive surgery with less reliance on intraoperative fluoroscopy, and lower radiation exposure to the surgeon and staff. As these technologies have become more widely adopted over the years, novel uses such as tumor resection have been explored. Disadvantages include the cost of implementing IG and robotics platforms, the initial learning curve for both the surgeon and the staff, and increased patient radiation exposure in scoliosis surgery. Also, given the relatively recent transition of many procedures from inpatient settings to ambulatory surgery centers, access to current devices may be cost prohibitive and not as readily available at some centers. Regarding patient-related outcomes, much further research is warranted. The short-term benefits of minimally invasive surgery often bolster the perioperative and early postoperative outcomes in many retrospective studies on IG and RA surgery. Randomized controlled trials limiting such confounding factors are warranted to definitively show potential independent improvements in patient-related outcomes specifically attributable to IG and RA alone. Nonetheless, irrespective of these current unknowns, it is clear that these technologies have changed the field and the practice of spine surgery. Surgeons should be familiar with the potential benefits and tradeoffs of these platforms when considering adopting IG and robotics in their practices.

Minimally Invasive Techniques for Iliac Bolt Placement: 2-Dimensional Operative Video

As the popularity of minimally invasive surgery (MIS) continues to grow, novel techniques are needed to meet the demands of multisegment fixation for advanced spinal diseases. In one such example, iliac bolts are often required to anchor large fusion constructs, but MIS technical notes are missing from the literature.  A 67-yr-old female presented with a symptomatic coronal deformity: preoperative pelvic incidence = 47°, pelvic tilt = 19°, and lumbar lordosis = 29°, sagittal vertical axis = +5.4 cm with 30° of scoliosis. The operative plan included T10-ilium fusion with transforaminal interbody grafts at L2-3, L3-4, L4-5, and L5-S1. The intraoperative video is of minimally invasive placement of iliac bolts using the O-Arm Surgical Imaging System (Medtronic®). The patient consented to the procedure.  A mini-open exposure that remains above the fascial planes allows for multilevel instrumentation with appropriate decompression at the interbody segments. After the placement of the pedicle screws under image-guidance, the direction is turned to the minimally invasive iliac bolts. Following the trajectory described in the standard open approach,1 the posterior superior iliac spine (PSIS) is identified with the navigation probe, which will guide the Bovie cautery through the fascia. This opening assists in the trajectory of the navigated-awl tap toward the anterior superior iliac spine (ASIS). Next, 8.5 mm x 90 mm iliac screws were placed in the cannulated bone under navigation. After intraoperative image confirmation of screw placement, the contoured rods are threaded under the fascia. The setscrews lock the rod in position. MIS approaches obviate cross-linking the rods, rendering pelvic fixation more facile.  This technique allows for minimal dissection of the posterior pelvic soft tissue while maintaining adequate fixation.

Navigated iliac screw placement may reduce radiation and OR time in lumbopelvic fixation of unstable complex sacral fractures

Purpose

Instability of the posterior pelvic ring may be stabilized by lumbopelvic fixation. The optimal osseous corridor for iliac screw placement from the posterior superior iliac spine to the anterior inferior iliac spine requires multiple ap- and lateral-views with additional obturator-outlet and -inlet views.

The purpose of this study was to determine if navigated iliac screw placement for lumbopelvic fixation influences surgical time, fluoroscopy time, radiation exposure, and complication rates.

Methods

Bilateral lumbopelvic fixation was performed in 63 patients. Implants were inserted as previously described by Schildhauer. A passive optoelectronic navigation system with surface matching on L4 was utilized for navigated iliac screw placement. To compare groups, demographics were assessed. Operative time, fluoroscopic time, and radiation were delineated.

Results

Conventional fluoroscopic imaging for lumbopelvic fixation was performed in 32 patients and 31 patients underwent the procedure with navigated iliac screw placement. No differences were found between the groups regarding demographics, comorbidities, or additional surgical procedures.

Utilization of navigation led to fluoroscopy time reduction of more than 50% (3.2 vs. 8.6 min.; p < 0.001) resulting in reduced radiation (2004.5 vs. 5130.8 Gy*cm²; p < 0.001). Operative time was reduced in the navigation group (176.7 vs. 227.4 min; p = 0.002) despite the necessity of additional surface referencing.

Conclusion

For iliac screws, identifying the correct entry point and angle of implantation requires detailed anatomic knowledge and multiple radiographic views. In our study, additional navigation reduced operative time and fluoroscopy time resulting in a significant reduction of radiation exposure for patients and OR personnel.

Evaluation of a Three-Dimensional Printed Guide and a Polyoxymethylene Thermoplastic Regulator for Percutaneous Pedicle Screw Fixation in Patients with Thoracolumbar Fracture

BACKGROUND This study aimed to evaluate the efficacy of a porous polyoxymethylene thermoplastic regulator combined with a three-dimensional (3D) printed template to guide pedicle needle insertion in patients undergoing percutaneous pedicle screw fixation (PPSF) for thoracolumbar fracture. MATERIAL AND METHODS Forty patients were randomly divided into group A, treated using a porous polyoxymethylene thermoplastic regulator combined with a 3D printed template, and group B, who underwent conventional PPSF. Data recorded included the number of pedicle screws successfully inserted on the first attempt, the number of attempts, the time to successful needle insertion, the total time of fluoroscopy, and the duration of surgery. The Visual Analogue Scale (VAS) and the Oswestry Disability Index (ODI) scores one day before surgery, and at day 1, day 7, month 1, and month 3 after surgery were recorded. The postoperative vertebral posterior kyphotic angle (KA) and the rate of change of KA were recorded. RESULTS Group A had a significantly increased total number of successful first insertions compared with group BV (P<0.05). Postoperative VAS and ODI scores of patients in both groups were significantly lower than before surgery (P<0.05), with no significant difference between the two groups at postoperative month 1 and month 3 (P>0.05). The postoperative vertebral posterior KA decreased significantly in both groups after surgery, with no significant difference between the two groups (P>0.05). CONCLUSIONS The use of a porous polyoxymethylene thermoplastic regulator combined with a 3D printed template may improve the success of pedicle insertion in patients undergoing PPSF.

Comparative tomographic study of the S2-alar-iliac screw versus the iliac screw

AIMS

Iliac screws and S2-alar-iliac screws provide adequate mechanical stability for the fixation of lumbosacral spine pathologies, which has led to a significant increase in the use of these techniques in the routine practice of spine surgeons. However, studies on the ideal technical positioning for both techniques are limited.

STUDY DESIGN

This is an observational, retrospective, analytical descriptive study.

OBJECTIVE

To analyze, describe and compare the insertion and positioning parameters of the S2-alar-iliac and iliac screw techniques in adult patients without spinal deformities.

METHODS

The present study comprises a retrospective analysis of lumbosacral computed tomography images selected continuously in 2016 from 25 patients at a university hospital. Mann-Whitney-Shapiro-Wilk tests were performed. Data reliability was assessed using intraclass correlation.

RESULTS

The mean length of the iliac screw was greater than that of the S2-alar-iliac screw, and the S2-alar-iliac screw sat 20.5 mm deeper than the iliac screw. The mean of the greatest bone thickness for the iliac screw was 20.72 mm; that of the S2-alar-iliac screw was 23.24 mm. The mean distance from the iliac screw entry point to the skin was 32.46 mm, and the mean distance from the S2-alar-iliac screw entry point to the skin was 52.87 mm.

CONCLUSION

The trajectory of the S2-alar-iliac screws studied via computed tomography was greater in terms of bone thickness and deeper relative to the skin compared with the iliac screws. The S2-alar-iliac technique may have desirable clinical advantages in terms of the diameter of the screws and reduced protrusion when used in adults. These slides can be retrieved from Electronic supplementary material.

Percutaneous and open iliac screw safety and accuracy using a tactile technique with adjunctive anteroposterior fluoroscopy

BACKGROUND CONTEXT

All currently described percutaneous iliac screw placement methods are entirely dependent on fluoroscopy.

PURPOSE

The purpose of this study was to determine the safety and the accuracy of percutaneous and open iliac screw placement using a primarily tactile technique with adjunctive anteroposterior (AP) fluoroscopy.

STUDY DESIGN/CONTEXT

All patients who underwent open and percutaneous iliac screw placement over a 5-year period were identified. Charts were reviewed to assess for any instances of neurologic or vascular injury associated with iliac screw placement. Screw accuracy was judged with postoperative computed tomography (CT) scans.

PATIENT SAMPLE

A total of 133 patients were identified who underwent open or percutaneous iliac screw placement. Computed tomography scans were available for 57 patients, and all of these patients were included in the study, with a total of 115 iliac screws.

OUTCOME MEASURES

Radiographic measurements were performed, consisting of the distance of the iliac screw to the sciatic notch on postoperative radiographs and CT scans. Computed tomography scans were used to determine iliac screw accuracy.

METHODS

Charts were reviewed to assess for any neurologic or vascular injuries related to screw placement. The distance of the iliac screw to the sciatic notch was measured and compared on AP radiography and CT scans. Computed tomography scans were assessed for any screw violation of the iliac cortex or the sciatic notch. The accuracy of open iliac screw placement was compared with minimally invasive percutaneous placement.

RESULTS

There were no neurologic or vascular injuries related to screw placement in the 133 patients. Computed tomography scans were available for 115 iliac screws, with 3 cortical breaches, all by less than 2 mm. All 112 other screws were accurately intraosseous. There was a strong correlation between the iliac screw to the sciatic notch distance when measured by CT scan compared with AP radiography (r=0.9), thus validating the accuracy of AP fluoroscopy in guiding iliac screw placement with respect to the sciatic notch. Iliac screw accuracy was equal with the open and percutaneous insertion techniques.

CONCLUSIONS

The described surgical technique represents a safe and reliable surgical option for iliac screw placement. Intraoperative AP fluoroscopy accurately reflects the distance of the iliac screw to the sciatic notch. Percutaneous iliac screws placed with this technique are as accurate as open iliac screws.

Safety and Accuracy of Freehand Versus Navigated Iliac Screws: Results From 222 Screw Placements

STUDY DESIGN

Retrospective review.

OBJECTIVE

To compare the safety and accuracy of the freehand technique versus stereotactic navigation for placement of iliac screws.

SUMMARY OF BACKGROUND DATA

Iliac screw fixation is often used to augment lumbosacral reconstruction in advanced spine disease to increase the likelihood of successful arthrodesis. Iliac screws can be placed with image guidance, using either intraoperative fluoroscopy or computed tomography (CT) to guide navigation. However, these imaging modalities add radiation exposure and can disrupt workflow. The freehand technique is an alternative strategy that decreases radiation exposure and workflow disruption but may compromise safety and accuracy.

METHODS

A retrospective review was performed for a consecutive series of adult patients with degenerative spine conditions who underwent posterior reconstruction with iliac screw placement between 2011 and 2016. Clinical and radiographic data were collected and analyzed. The accuracy of iliac screw placement was determined with either intraoperative/postoperative CT imaging or anteroposterior/lateral radiography when CT was not performed.

RESULTS

Bilateral iliac screws were placed in all 111 patients, for a total of 222 iliac screws. Eighty screws were placed with the freehand technique and 142 with the intraoperative navigation technique. CT imaging was used to assess placement accuracy of 124 screws (46 freehand [37%], 78 navigated [63%]). Accuracy was similar for the freehand group (89%, 41/46) and the navigated group (96%, 75/78) (P = 0.12). For patients without intraoperative/postoperative CT imaging, radiography was used to assess placement accuracy of 98 screws (34 freehand, 64 navigated) and the placement accuracy rate for the freehand group (100%, 34/34) was comparable to that for the navigated group (98%, 63/64) (P = 0.46). No complications attributable to iliac screw placement occurred in either group.

CONCLUSION

Overall, there was no difference in the safety and accuracy between the freehand and navigated techniques.

LEVEL OF EVIDENCE

4.

Robotic Guidance for S2-Alar-Iliac Screws in Spinal Deformity Correction

STUDY DESIGN

A retrospective cohort study of patients who underwent S2-alar-iliac (S2AI) screw insertion using robotic guidance in long constructs for spinal deformity correction extending to the sacrum performed at a single institution.

OBJECTIVE

To assess and evaluate the feasibility and accuracy of robotic guidance for S2AI screw insertion.

SUMMARY OF BACKGROUND DATA

Pelvic fixation has become a common adjunct to long fusions extending to the sacrum. The S2AI method possesses advantages over the traditional Galveston technique. S2AI involves finding a pathway from S2 across the sacral ala and the sacroiliac joint into the ilium. Robotic guidance is a new modality for implant insertion that has shown high accuracy.

METHODS

We identified all patients who underwent robotic-guided S2AI screw insertion in long constructs extending to the sacrum. Cortical breaches and protrusions, assessed on postoperative imaging, and complications were recorded.

RESULTS

Fourteen patients (31 screws) underwent S2AI screw insertion using robotic guidance and free-hand probing. Average screw length was 80 mm (range, 65-90 mm). All trajectories were confirmed as accurate (no proximal breaches). Screw insertion, performed manually, resulted in 10 protrusions <2 mm, 1 by 2-4 mm, and 6 by ≥4 mm. No screw was intrapelvic or risked any visceral or neurovascular structures and none required removal or revision. Longer screws (>80 mm) were associated with distal protrusion.

CONCLUSIONS

Robotic-guided S2AI screws are accurate and a feasible option. Although no complications from protrusion were identified, larger studies and instrumentation modifications are required to assess the clinical acceptance of robotic guidance in sacropelvic fixation.

Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation

We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy.

3D Rapid Prototyping for Otolaryngology-Head and Neck Surgery: Applications in Image-Guidance, Surgical Simulation and Patient-Specific Modeling

The aim of this study was to demonstrate the role of advanced fabrication technology across a broad spectrum of head and neck surgical procedures, including applications in endoscopic sinus surgery, skull base surgery, and maxillofacial reconstruction. The initial case studies demonstrated three applications of rapid prototyping technology are in head and neck surgery: i) a mono-material paranasal sinus phantom for endoscopy training ii) a multi-material skull base simulator and iii) 3D patient-specific mandible templates. Digital processing of these phantoms is based on real patient or cadaveric 3D images such as CT or MRI data. Three endoscopic sinus surgeons examined the realism of the endoscopist training phantom. One experienced endoscopic skull base surgeon conducted advanced sinus procedures on the high-fidelity multi-material skull base simulator. Ten patients participated in a prospective clinical study examining patient-specific modeling for mandibular reconstructive surgery. Qualitative feedback to assess the realism of the endoscopy training phantom and high-fidelity multi-material phantom was acquired. Conformance comparisons using assessments from the blinded reconstructive surgeons measured the geometric performance between intra-operative and pre-operative reconstruction mandible plates. Both the endoscopy training phantom and the high-fidelity multi-material phantom received positive feedback on the realistic structure of the phantom models. Results suggested further improvement on the soft tissue structure of the phantom models is necessary. In the patient-specific mandible template study, the pre-operative plates were judged by two blinded surgeons as providing optimal conformance in 7 out of 10 cases. No statistical differences were found in plate fabrication time and conformance, with pre-operative plating providing the advantage of reducing time spent in the operation room. The applicability of common model design and fabrication techniques across a variety of otolaryngological sub-specialties suggests an emerging role for rapid prototyping technology in surgical education, procedure simulation, and clinical practice.

Free-hand placement of iliac screws for spinopelvic fixation based on anatomical landmarks: technical note

Background

The placement of iliac screws is a biomechanically sound method for the stabilization of long multi-segment lumbar constructs. Traditional techniques for the placement of iliac screws often involve either substantial iliac muscle dissection for visualization of screw trajectory based on bony landmarks, or alternatively the use of intra-operative imaging to visualize these landmarks and guide screw placement. We describe an alternative free-hand method of iliac screw placement, one that needs neither significant muscle dissection nor intra-operative imaging.

Methods

We performed this technique in 10 consecutive patients. Patient demographics, spinal pathology, post-operative complications, and screw hardware characteristics are described.

Results

We have successfully used this technique for the placement 20 iliac screws based on anatomic landmarks in 10 consecutive patients. There were no cortical breeches of the ileum and no penetrations into the acetabulum on post-operative imaging. There were no instances of hardware failure. Two patients developed deep vein thromboses after surgery, 1 had a pulmonary embolism.

Conclusions

Based on our limited experience to date, free-hand placement of iliac screws is both easy to perform and safe for the patient. Further study and validation using this technique is warranted.

Accuracy of intraoperative computed tomography image-guided surgery in placing pedicle and pelvic screws for primary versus revision spine surgery

OBJECT

Revision spine surgery, which is challenging due to disrupted anatomy, poor fluoroscopic imaging, and altered tactile feedback, may benefit from CT image-guided surgery (CT-IGS). This study evaluates accuracy of CT-IGS-navigated screws in primary versus revision spine surgery.

METHODS

Pedicle and pelvic screws placed with the O-arm in 28 primary (313 screws) and 33 revision (429 screws) cases in which institutional postoperative CT scans were available were retrospectively reviewed for placement accuracy. Screw accuracy was categorized as 1) good (< 1-mm pedicle breach in any direction or "in-out-in" thoracic screws through the lateral thoracic pedicle wall and in the costovertebral joint); 2) fair (1- to 3-mm breach); or 3) poor (> 3-mm breach).

RESULTS

Use of CT-IGS resulted in high rates of good or fair screws for both primary (98.7%) and revision (98.6%) cases. Rates of good or fair screws were comparable for the following regions: C7-T3 at 100% (good or fair) in primary versus 100% (good or fair) in revision; T4-9 at 96.8% versus 100%; T10-L2 at 98.2% versus 99.3%; L3-5 at 100% versus 99.2%; and pelvis at 98.7% versus 98.6%, respectively. On the other hand, revision sacral screws had statistically significantly lower rates of good placement compared with primary (100% primary vs 80.6% revision, p = 0.027). Of these revision sacral screws, 11.1% had poor placement, with bicortical screws extending > 3 mm beyond the anterior cortex. Revision pelvic screws demonstrated the highest rate of fair placement (28%), with the mode of medial breach in all cases directed into the sacral-iliac joint.

CONCLUSIONS

In the cervical, thoracic, and lumbar spine, CT-IGS demonstrated comparable accuracy rates for both primary and revision spine surgery. Use of 3D imaging of the bony pedicle anatomy appears to be sufficient for the spine surgeon to overcome the difficulties associated with instrumentation in revision cases. Although the bony structures of sacral pedicles and pelvis are relatively larger, the complexity of local anatomy was not overcome with CT-IGS, and an increased trend toward inaccurate screw placement was demonstrated.

Percutaneous pedicle screw placement with computer-navigated mapping in place of Kirschner wires: clinical article

OBJECT

Percutaneous pedicle screw insertion techniques are commonly used to treat a variety of spinal disorders. Typically, Kirschner (K)-wires are used to guide the insertion of taps and screws during placement since the normal anatomical landmarks are not visualized. The use of K-wires adds risks, such as vascular and nerve injuries as well as increased radiation exposure given the use of fluoroscopy. The authors describe a series of patients who had percutaneous pedicle screws placed using a new computer-assisted navigation technique without the need for K-wires.

METHODS

Minimally invasive percutaneous pedicle screw placement in the thoracic and lumbar spine was performed in a consecutive series of 15 patients for a variety of spinal pathologies. Intraoperative 3D CT images were obtained and used with a computer-assisted navigation system to insert an awl-tap into each pedicle. The tap location in the pedicle was marked with the navigation software, and the awl-tap was then removed. The navigation system was used to identify each landmark to insert the pedicle screw. Connecting rods were then inserted percutaneously under fluoroscopic guidance. Postoperative CT scans were obtained in each patient to evaluate screw placement.

RESULTS

On postprocedure scanning, only 1 screw had a minor lateral and superior breach that was asymptomatic. To date, there have been no hardware failures.

CONCLUSIONS

Percutaneous pedicle screws can be placed effectively and safely without the use of K-wires.

Mini-open stabilization of a sacral fracture: technical case report

BACKGROUND AND IMPORTANCE

Comminuted sacral fractures present significant challenges for operative management. Open and percutaneous sacroiliac screws have been used for stabilization but carry not insignificant rates of complications, including wound infection for the former and malposition and neurological injury for the latter. We report the use of a novel mini-open lumbar-ilium fixation for stabilization of a patient with a comminuted sacral fracture.

CLINICAL PRESENTATION

A 33-year-old man with intact neurologic function was admitted after a fall of approximately 25 ft. A comminuted sacral fracture was diagnosed. The patient was unable to tolerate conservative management because of pain in upright positions. The patient was taken to the operating room for stabilization with a "mini-open" procedure involving L4 and L5 pedicle screws and bilateral iliac screws. Four 2-in paramedian incisions were made overlying the L4-L5 facet joints and medial to the sacroiliac joints. Minimally invasive retractors were placed to expose bony landmarks. L4-L5 pedicle screws and bilateral iliac screws were placed with minimal fluoroscopic guidance. Titanium rods were tunneled inferior-superiorly between incisions and affixed to screw heads. Total operative time was approximately 3.5 hours. The patient remained neurologically intact and had an uncomplicated recovery. One-year follow-up computed tomography showed successful healing of the sacrum.

CONCLUSION

We report the first case of a mini-open procedure to treat a comminuted sacral fracture. Use of this procedure offers a straightforward method for sacral stabilization with minimal blood loss and minimal radiation exposure. If indicated, this method could be combined with decompressive procedures.

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.

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.