Cervical Pedicle Screw Fixation Research Articles

Complications associated with subaxial placement of pedicle screws versus lateral mass screws in the cervical spine: systematic review and meta-analysis comprising 1768 patients and 8636 screws.

Lateral mass screw (LMS) fixation for the treatment of subaxial cervical spine instability or deformity has been traditionally associated with few neurovascular complications. However, cervical pedicle screw (CPS) fixation has recently increased in popularity, especially with navigation assistance, because of the higher pullout strength of the pedicle screws. To their knowledge, the authors conducted the first meta-analysis comparing the complication rates during and/or after CPS and LMS placement for different pathologies causing cervical spine instability. A systematic literature search of PubMed and Embase from inception to January 12, 2021 was performed to identify studies reporting CPS and/or LMS-related complications. Complications were categorized into intraoperative and early postoperative (within 30days of surgery) and late postoperative (after 30days from surgery) complications. All studies that met the prespecified inclusion criteria were pooled and cumulatively analyzed. A total of 24 studies were conducted during the time frame of the search and comprising 1768 participants and 8636 subaxially placed screws met the inclusion criteria. The CPS group experienced significantly more postoperative C5 palsy (odds ratio [OR] = 3.48, 95% confidence interval [CI] = 1.27-9.53, p < 0.05). Otherwise, there were no significant differences between the LMS and CPS groups. There were no significant differences between the CPS and LMS groups in terms of neurovascular procedure-related complications other than significantly more C5 palsy in the CPS group.

Medial Pedicle Pivot Point Using Preoperative Computed Tomography Morphometric Measurements for Cervical Pedicle Screw Insertion: A Novel Technique and Case Series.

This study describes a new and safe freehand cervical pedicle screw insertion technique using preoperative computed tomography (CT) morphometric measurements as a guide and a medial pedicle pivot point (MPPP) during the procedure. This study included 271 pedicles at 216 cervical spine levels (mean: 4.75 pedicles per patient). A pedicle diameter (PD) ≥ 3.5 mm was the cut-off for pedicle screw fixation. The presence and grade of perforation were detected using postoperative CT scans, where perforations were graded as follows: 0, no perforation; 1, perforation < 0.875 mm; 2, perforation 0.875–1.75 mm; and 3, perforation > 1.75 mm. The surgical technique involved the use of an MPPP, which was the point at which the lines representing the depth of the lateral mass and total length of the pedicle intersected, deep in the lateral mass. The overall success rate was 96.3% (261/271, Grade 0 or 1 perforations). In total, 54 perforations occurred, among which 44 (81.5%) were Grade 1 and 10 (18.5%) were Grade 2. The most common perforation direction was medial (39/54, 72.2%). The freehand technique for cervical pedicle screw fixation using the MPPP may allow for a safe and accurate procedure in patients with a PD ≥3.5 mm.

Robotic-guided placement of cervical pedicle screws: feasibility and accuracy.

It has been shown that pedicle screw instrumentation in the cervical spine has superior biomechanical pullout strength and stability. However, due to the complex and variable anatomy of the cervical pedicles and the risk of catastrophic complications, cervical pedicle screw placement is not widely utilized. A retrospective, consecutive patient review. To review and reportour experience with robotic guided cervical pedicle screw placement. We retrospectively reviewed preoperative and postoperative CT scans of 12 consecutive patients who underwent cervical pedicle screw fixation with robotic guidance. Screw placement and deviation from the preoperative plan were assessed using the robotic system's planning software by fusing the preoperative CT (with the planned cervical pedicle screws) to the post-op CT. This process was carried out by manually aligning the anatomical landmarks on the two CTs. Once a satisfactory fusion was achieved, the software's measurement tool was used manually to compare the planned vs. actual screw placements in the axial, sagittal and coronal planes within the instrumented pedicle in a resolution of 0.1mm. Medical charts were reviewed for technical issues and intra-operative complications. Eighty-eight cervical pedicle screws were reviewed in 12 patients; mean age = 65years, M:F = 2:1, and mean BMI = 27.99. No intra-operative complications related to the cervical pedicle screw placement were reported. Robotic guidance was successful in all 88 screws: eight in C2, 14 in C3, 16 in each of C4 and C5, 19 in C6, and 15 at C7. There were 14 pedicle screw breaches (15.9%); all were medial, less than 1mm, and with no clinical consequences. In the axial plane, the screws deviated from the preoperative plan by 1.32 ± 1.17mm and in the sagittal plane by 1.27 ± 1.00mm. In the trajectory view, the overall deviation was 2.20 ± 1.17mm. Although differences were observed in screw deviation from the pre-op plan between the right and left sides, they were not statistically significant (p > 0.05). This study indicates that robotic-guided cervical pedicle screw placement is feasible and safe. The medial breaches did not result in any clinical consequences.

Ten-year clinical and radiographic results of computer-assisted cervical pedicle screw fixation combined with laminoplasty

ObjectiveCervical pedicle screw (CPS) fixation is widely used for the treatment of cervical spinal instability from various causes; however, there are few reports on the long-term outcomes of this procedure. The present study evaluated the 10-year results of CPS fixation for cervical instability. MethodsThe medical records of 13 consecutive patients who underwent computer-guided CPS fixation for cervical instability were reviewed. The mean observation period was 153 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 and 10 years afterwards. Visual analog scale (VAS) scores for neck pain and radiological evidence of adjacent segment degeneration (ASD) at 10 years of follow-up were also assessed. ResultsMean JOA score significantly improved from 9.4 points before surgery to 13.2 points at 5 years after surgery (p < 0.001), followed next by a slight reduction to 11.6 points at 10 years postoperatively. C2-7 lordotic angle tended to decrease from 7.9° preoperatively to 5.3° at 10 years after surgery. No clinically significant complications, such as neurovascular injury caused by screw misplacement, were observed. The mean VAS score for neck pain was 31.7 points at the study endpoint, and ASD rate was 23.1%. ConclusionsAt 10 years after CPS fixation, mean JOA score was improved without symptoms indicative of cervical myelopathy recurrence. Our long-term results confirm that computer-assisted CPS fixation is useful for treating cervical instability.

The comparative accuracy and safety of fluoroscopic and navigation-based techniques in cervical pedicle screw fixation: systematic review and meta-analysis.

The goal of this study was to evaluate the comparative accuracy and safety of navigation-based approaches for cervical pedicle screw (CPS) placement over fluoroscopic techniques. A systematic search of the literature published between January 2006 and December 2019 relating to CPS instrumentation and the comparative accuracy and safety of fluoroscopic and intraoperative computer-based navigation techniques was conducted. Several databases, including the Cochrane Library, PubMed, and EMBASE, were systematically searched to identify potentially eligible studies. Data relating to CPS insertion accuracy and associated complications, in particular neurovascular complications, were extrapolated from the included studies and summarized for analysis. A total of 17 studies were identified from the search methodology. Eleven studies evaluated CPS placement under traditional fluoroscopic guidance and 6 studies addressed outcomes following navigation-assisted placement (3D C-arm or CT-guided placement). Overall, a total of 4278 screws were placed in 1065 patients. Misplacement rates of CPS were significantly lower (p < 0.0001) in navigation-assisted techniques (12.51% [range 2.5%-20.5%]) compared to fluoroscopy-guided techniques (18.8% [range 0%-43.5%]). Fluoroscopy-guided CPS insertion was associated with a significantly higher incidence of postoperative complications relating to neurovascular injuries (p < 0.038), with a mean incidence of 1.9% compared with 0.3% in navigation-assisted techniques. This systematic review supports a logical conclusion that navigation-based techniques confer a statistically significantly more accurate screw placement and resultant lower complication rates.

Versatile Usage of the Modified Lateral Mass Screw as an Alternative to Cervical Pedicle Screw Fixation.

Posterior subaxial cervical screw fixation is commonly performed using the cervical pedicle screws (CPS) and lateral mass screws (LMS); however, their compatibility is low. Modified lateral mass screws (mLMS, also called paravertebral foramen screw) fixation was introduced as a salvage technique for LMS fixation and has features of both LMS and CPS techniques. In the present study, the use of mLMS as an alternative to CPS was analyzed based on clinical results. Seventy-eight screws (38 CPSs and 40 mLMSs) were inserted into 12 patients. The misplacement of the screws was evaluated by computed tomography (CT). The failure of instrumentation and instability were evaluated using plain radiographs. The total number of CPS misplacements was 3 (10.5%); however, neurologic complications were not observed. mLMSs were used in the middle segments of the fusion in 10 patients and 2 patients had mLMS fixation for single-level fusion. An additional bridging implant was not required for connecting both CPSs and mLMSs. Instability was not observed during the observation period (4-51 months). Complete fusion was seen in 10 patients. The alternative mLMS fixation can decrease the risk of screw misplacement compared with CPS fixation alone and achieves adequate stability leading to fusion.

Comparative evaluation of screw accuracy and complications of new C-arm free O-arm navigated minimally invasive cervical pedicle screw fixation (MICEPS) with conventional cervical screw fixation

Study designRetrospective comparative study. ObjectiveComparative study of C-arm free O-arm navigated minimally invasive cervical pedicle screw (MICEPS) fixation with conventional cervical pedicle screw fixation. MethodsTwenty-five patients with different cervical spine pathologies were operated with MICEPS with O-arm navigation (group M; 18 patients) and conventional pedicle screw (group C; 7 patients) from June 2017 to January 2020. Operative time, blood loss were recorded. Preoperative and postoperative radiograms, CT scans and MRI were evaluated. Postoperatively screw position accuracy and angulation was determined on CT. Breach rate was evaluated on CT scan and classified according to Neo grading. Complications if any were noted. ResultsThe average blood loss in group M and group C was 129 ml and 329 ml, respectively. The average operative time in group M and group C was 77.4 min and 82.3 min, respectively. A total of 148 screws were inserted. In group M, no patient showed grade 2 and 3 breach while in group C, grade 0 and 1 breach was found in 85.7% screws and grade 2 in 14.3% screws. Mean screw medial angulation was 45.2 degrees in group M and 33.4 degrees in group C. There was one dural tear and two C5 palsies in each group. ConclusionWith C -arm free O-arm navigated MICEPS fixation operative time and blood loss are less though not statistically significant. It has less pedicle breach rate, less incidence of neurovascular complications than conventional technique. There is no radiation exposure to operating surgeon and staff.

Single-Stage Posterior Approach for Multilevel Cervical Ossification of the Posterior Longitudinal Ligament With K-line (-) Using Thick Cervical Pedicle Screw System: A Technical Note and Preliminary Results.

Technical note, retrospective case series. The optimal surgical strategy for multilevel cervical ossification of the posterior longitudinal ligament (OPLL) with a negative kyphosis line (K-line (-)) remains controversial. We present a novel single-stage posterior approach that converts the K-line from negative to positive in patients with multilevel cervical OPLL, using a posterior thick cervical pedicle screw (CPS) system and report the procedure's outcomes and feasibility. Twelve consecutive patients with multilevel cervical OPLL and K-line (-) underwent single-stage posterior thick CPS fixation, with laminectomy and foraminal decompression. A pre-bent rod was installed to convert the K-line from negative to positive. Radiographic parameters, including the extent and occupying ratio of OPLL and the C2-C7 angle, were examined. CPS accuracy was assessed using computed tomography. The Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores were analyzed. Quality of life was assessed using the Neck Disability Index (NDI). The mean OPLL extent was 5 vertebral body levels, and posterior decompression was performed on 4.2 segments. The average C2-C7 angle and the occupying ratio of OPLL improved from -9.0° to 14.3° and from 63% to 33%, respectively. The preoperative JOA, VAS, and NDI scores significantly improved from 8.4 to 13.3, from 7.1 to 2.2, and from 21.9 to 9.3, respectively. The K-line was converted from negative to positive in all cases. No severe complications were identified. Single-stage posterior surgery with a thick CPS system may be a reliable and effective treatment for multilevel cervical OPLL and K-line (-).

Is Standalone Posterior Cervical Pedicle Screw Fixation Sufficient to Correct Cervical Postlaminectomy Kyphosis?

To evaluate the clinical processes of patients with cervical postlaminectomy kyphosis (PLK) who underwent standalone posterior pedicle screw fixation surgery. The results of 21 patients with cervical PLK treated using the pedicle screw method between 2015 and 2018 were retrospectively examined. Patient data included demographic information and indications for surgery. Furthermore, the following criteria were calculated for each patient: cervical sagittal vertical axis (cSVA), C2-7 cervical lordosis (CL) parameters, modified Japanese Orthopaedic Association (mJOA) score, Neck Disability Index (NDI) score and visual analogue scale score, and these were evaluated preoperatively and postoperatively statistically. A total of 21 patients with PLK were evaluated. In terms of radiographic parameters, postoperative cSVA was significantly lower than the preoperative cSVA, and postoperative CL was significantly higher than the preoperative CL (p < 0.001, p < 0.001, respectively). Postoperative mJOA scores were significantly higher than the preoperative scores (p < 0.001). Both postoperative NDI and VAS scores were significantly lower than the preoperative scores (p < 0.001, p < 0.001 respectively). Pedicle screw fixation was found to be an effective treatment for cervical PLK. Although this technique is not preferred by many spine surgeons because of its high complication rate, it has a positive effect on the quality of life scores and provides optimal correction.

C-Arm-Free Minimally Invasive Cervical Pedicle Screw Fixation (MICEPS): A Technical Note.

A minimally invasive posterolateral approach designed to avoid the lateral misplacement of midcervical pedicle screws was reported, but there is no technical report that describes this technique without C-arm fluoroscopy. We report the results of a 2.5 years follow-up of a 62-year-old female patient with C4 metastatic breast cancer. The patient suffered from severe neck pain and impending quadriplegia for 2 months after radiation therapy. We performed C-arm-free minimally invasive cervical pedicle screw fixation (MICEPS). The patient was suc-cessfully treated with surgery, and her neck pain was well controlled. She had neither neurological deficits nor neck pain at the final (2.5-year) follow-up. C-arm-free MICEPS is a useful technique; in addition, the sur-geons and staff have no risk of radiation exposure, there is a reduced need for postoperative imaging, and a decreased revision rate can be expected with C-arm-free MICEPS.

The accuracy of a novel pedicle screw insertion technique assisted by a special angular scale in the subaxial cervical spine using lateral mass as a reference marker

BackgroundPosterior cervical pedicle screw (CPS) internal fixation has better biomechanical stability than other posterior cervical fixation methods. However, this technique is limited in clinical practice due to the complex anatomical structure and the adjacent relationship of the cervical pedicle, and the high risk of neurovascular injury. The purpose of this study was to describe a novel subaxial CPS insertion technique assisted by a special angular scale using lateral mass as a reference marker and to evaluate the accuracy of CPS placement and the distribution characteristics of CPS misplacement.MethodsA total of 36 patients with subaxial cervical spine diseases who underwent posterior CPS fixation were consecutively selected. The optimal entry point on the posterior surface of the lateral mass was identified on the three-dimensional cervical model reconstructed from preoperative computed tomography (CT) images. The pedicle transverse angle (PTA) and pedicle-lateral mass angle (PLMA) were measured on the transverse and sagittal CT images respectively. The pedicle screws were inserted according to the preoperatively planned entry point and angles. We analysed the postoperative CT images for CPS misplacement rates and perforation directions following the Lee classification.ResultsOverall, 177 pedicle screws were inserted, of which 119 (67.2%) were classified as grade 0, 43 (24.3%) as grade 1, 12 (6.8%) as grade 2 and 3 (1.7%) as grade 3 by the postoperative CT images. The accuracy rate of CPS placement was 91.5%. Of the 15 misplaced pedicle screws (grades 2 and 3), 11 were lateral pedicle perforations, 3 were superior perforations and 1 was an inferior perforation. There were no neurovascular injuries related to CPS misplacement.ConclusionsWith our technique, the optimal entry point and two angles (PTA and PLMA) were identified for CPS insertion. The novel CPS insertion technique assisted by a special angular scale provides high accuracy and few complications.

Percutaneous, Navigated Minimally Invasive Posterior Cervical Pedicle Screw Fixation.

Cervical pedicle screws provide significant biomechanical advantage but can be technically challenging and associated with morbid exposure. Improvements in intraoperative navigation guidance and instrumentation have made feasible this biomechanically robust, but technically challenging procedure. We present our initial experience with minimally invasive (MIS) percutaneous pedicle screw fixation in the cervical atlantoaxial and subaxial spine. A retrospective review was performed on 27 cases that involved a novel MIS percutaneous cervical pedicle screw technique. Small lateral skin incisions were made bilaterally on the neck using intraoperative navigation guidance. Subsequently, navigated, percutaneous screws were placed using the Proficient Minimally Invasive System (PROMIS; Spine Wave, Shelton, CT). Computed tomography (CT)-guided navigation was used for cervical pedicle screw placement with subsequent placement of percutaneous rods. Indications for surgery included type II odontoid fractures, subaxial fracture dislocations and burst fracture, metastatic pathological burst fracture, and degenerative spondylosis with stenosis. There were 15 men and 12 women, with an average age 63.5 years. Follow-up ranged from 3 to 24 months (average = 16.7 months). One screw was revised intraoperatively. Two patients (7.7%) required reoperation, 1 patient required repositioning of a C5 pedicle screw, and 1 suffered a C7 body fracture. No nerve root injury, spinal cord injury, or vertebral artery injuries were reported. Percutaneous cervical pedicle screw fixation is a feasible and safe technique when performed with CT-guided intraoperative navigation techniques. Cervical pedicle screw fixation provides a biomechanically superior construct in comparison with a lateral mass technique. In addition, the lack of paraspinal muscle disruption preserves important stabilizers of the posterior ligamentous complex and may reduce wound-healing issues in high-risk cases (eg, trauma patients). Although the current role for percutaneous instrumentation is relatively narrow, the advancement of MIS posterior cervical techniques may provide expanded opportunities in the future.

Intraoperative O-arm navigation guided anterior cervical corpectomy and fusion with minimally invasive cervical pedicle screw fixation (MICEPS) for severe ossification of the cervical posterior longitudinal ligament (OPLL): A technical note

BackgroundAnterior cervical corpectomy and fusion (ACCF) with floating technique is one of the best surgical interventions for severe ossification of the posterior longitudinal ligament (OPLL). However, insufficient decompression and a thinned ossification mass often lead to poor clinical outcome. This report describes a novel floating technique with intraoperative O-arm navigation to facilitate surgical treatment of the OPLL, which has not previously been described as a therapeutic option. Case descriptionAn 82-year-old woman with myelopathy of the OPLL was referred to our hospital. Activities of daily living had been restricted by severe left arm pain, myelopathy hand, and gait disturbance for 3 years. ACCF was performed under the guidance of O-arm navigation and C-arm-free minimally invasive cervical pedicle screw fixation (MICEPS). The patient was successfully treated surgically and manual muscle test results and sensory function of the left arm had recovered fully by final follow-up at 1 year. Japanese Orthopedic Association score of the patient had improved from 10/17 to 16/17. ConclusionsIntraoperative O-arm navigation-guided ACCF with C-arm-free MICEPS is an effective technique for achieving precise decompression and strong, minimally invasive fixation. This new anterior navigation technique provides an excellent result for severe OPLL without the risk of adverse events from intraoperative radiation.

Accurate and Minimally Invasive Cervical Pedicle Screw Insertion Procedure Using the Bone Biopsy Needle as Drill Guide.

Introduction Cervical pedicle screw (CPS) fixation provides the strongest mechanical stability. It needs, however, wide soft tissue detachment to expose the entry point and carries the potential risk of iatrogenic damage to neurovascular structures. Malposition of the CPS cannot be completely avoided even using the navigation system. Technical Note Using the bone biopsy needle as drill guide, we developed a novel accurate CPS insertion technique. (1) The entry point of CPS was exposed using Southwick's technique for anterior fixation or Tokioka's technique for posterior fixation. (2) A 13G bone biopsy needle was inserted from the entry point established by the fluoroscopy-assisted pedicle axis view technique described by Yukawa et al. to within a few millimeters of the pedicle. (3) The external sleeve of the bone biopsy needle was left in place as a drill guide, and the 1.25 mm guidewire for a 4.0 mm cannulated screw was then inserted into the pedicle cavity. (4) The external sleeve of the bone biopsy needle was removed, and the screw trajectory was created by a 2.7 mm cannulated drill bit over the guidewire. (5) Tapping was conducted prior to CPS insertion. Using this method, 29 CPSs in nine patients were inserted. Postoperative computed tomography scans revealed that all the CPSs were placed accurately. Conclusions Utilizing the bone biopsy needle as drill guide, our procedure enables accurate positioning of CPS without expensive instruments.

Augmented Reality Supported Cervical Transpedicular Fixation on 3D-Printed Vertebrae Model: An Experimental Education Study.

To investigate the use of Augmented Reality (AR) technology as it contributes to spinal surgery education with the free-hand technique, and might reduce the error ratio. Ten candidates, with anatomy education but no surgical experience, applied 36 pedicle screws with C2-C3 posterior transpedicular fixation technique to nine vertebrae models produced via a three-dimensional (3D) printer. Using AR to apply pedicle screws to the experimental vertebrae model increased the safety screw ratio significantly. In comparison of Grade 0 screws to other grades: 6/18 screws (33.3%) in the free-hand technique Group (n=18), and 14/18 screws (77.8%) in the AR Group (n=18), were measured for screw insertion safety ratios. The difference was statistically significant (p=0.018). The resemblance between our results and the results of previous studies researching supportive systems indicates our 3D printed vertebra model might be a helpful educational material. AR increases the safety ratio of cervical pedicle screw fixation significantly. The parameters investigated and used for the production of vertebrae models in this study can be used for experimental material production for future studies to investigate pedicle screw positioning.

237. Robotic-guided placement of cervical pedicle screws: feasibility and accuracy

BACKGROUND CONTEXT It has been shown that pedicle screw instrumentation in the cervical spine has superior biomechanical pullout strength and stability. However, due to the complex and variable anatomy of the cervical pedicles and the risk of catastrophic complications, cervical pedicle screw placement is not widely utilized. PURPOSE The purpose of this study is to review and report our experience with robotic guided cervical pedicle screw placement. STUDY DESIGN/SETTING We retrospectively reviewed consecutive patients who underwent cervical pedicle screw fixation with robotic guidance using pre- and postoperative CT scans by the investigator. Medical charts were reviewed for technical issues and intraoperative complications. PATIENT SAMPLE A total of 62 cervical pedicle screws were reviewed in eight consecutive patients. OUTCOME MEASURES Screw placement and deviation (mm) from the preoperative plan were assessed.We also reviewed the Medical charts for technical issues and intra-operative complications. METHODS Screw placement and deviation from the preoperative plan were assessed using the robotic system's planning software by fusing the preoperative CT (with the planned cervical pedicle screws) to the postoperative CT. This process was carried out by manually aligning the anatomical landmarks on the two CTs. Once a satisfactory fusion was achieved, the software's measurement tool was used manually to compare the planned vs actual screw placements in both axial and sagittal planes, at the midpoint of the pedicle in a resolution of 0.1 millimeters. Medical charts were reviewed for technical issues and intraoperative complications. RESULTS A total of 62 cervical pedicle screws were reviewed in eight patients. The patients’ mean age was 65 years, M:F ratio was 1:1, and the mean BMI was 25.17. No intraoperative complications that related to the placement of cervical pedicle screws were reported and robotic-guidance was successful in all 62 screws. The number of screws placed were 8 at C2, 12 at both C3 and C4, 10 at C5, 11 at C6, and 9 at C7. Postoperative CT scans showed that there were ten pedicle screw breaches (16.1%), all were medial, all less than 1 mm, with no clinical consequences. No pedicle screw breached the foramen transversarium. In the axial plane, the left side screws deviated from the pre-operative plan by 1.2±0.76 mm and the right-side screws deviated from the preoperative plan by 1.4±1.16 mm. In the sagittal plane, the left side screw deviated from the pre-operative plan by 1.2±1.16 mm and the right-side screw deviated from the preoperative plan by 1.4±0.94 mm. CONCLUSIONS This study indicates that robotic-guided cervical pedicle screw placement is feasible with clinically acceptable results. The medial breaches did not result in any clinical consequences akin to passing a sublaminar wire or placing a hook into the epidural space. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Minimally Invasive Cervical Pedicle Screw Fixation (MICEPS) via a Posterolateral Approach.

Cervical pedicle screw (PS) fixation provides great mechanical strength; however, it needs wide soft tissue detachment and has vertebral artery damage risk. Minimally invasive cervical pedicle screw (MICEPS) fixation, a new method for cervical PS fixation through a posterolateral approach, was developed to reduce soft tissue damage and avoid lateral misplacement of screws. Sixty-seven patients with cervical injury underwent MICEPS fixation. They were positioned prone on a radiolucent carbon table with a carbon Mayfield frame. A reference frame was attached to the spinous process through a small skin incision. One or 2 lateral incisions were made for screw insertion under navigation guidance. After the nuchal fascia was cut, the lateral mass was exposed with blunt dissection between the levator scapulae and splenius muscles. A self-retaining tubular retractor with illumination was applied between split muscle fibers. A 1.4-mm K-wire was inserted using an electric driver under navigation guidance. Drill and tap and cannulated PSs were sequentially inserted over the K-wire; facet fusion via bone grafting can be performed at this time. The rod was placed to the screw head. This technique can reduce intraoperative bleeding and screw deviation rate, with neither of the misplaced screws deviating laterally in the MICEPS group.

Evaluation of Multi-Slice Spiral Computed Tomography in In vivo Simulation of Individualized Cervical Pedicle Screw Placement at C3-C7 in Chinese Healthy Population.

Background:Cervical pedicle screw fixation through posterior approach has shown greater cervical stability advantage. The cervical pedicle screw fixation technique through posterior approach is demanding. The key to the technique is the choice of point and angle of screw entrance. The angle of screw placement is variable. Morphometric measurements of the cervical pedicle are a prerequisite for individualized screw. CT imaging has become the most reliable and important means to obtain cervical pedicle's measurement data and morphology in vivo. This study explores the feasibility and application of precise in vivo measurements by multi-slice computed tomography (MSCT) for individualized cervical transpedicular screw placement at C3–C7 in Chinese healthy population.Materials and Methods:80 adults who underwent cervical examination by enhanced and nonenhanced computed tomography angiography, respectively, were selected and submitted to bone algorithm reconstruction for slice thickness and interval of 0.75 mm to acquire clear images and detailed bone structures. Simulation of individualized screw placement was performed with a 4.0 mm diameter screw with the help of postprocessing workstation. Pedicle transverse angle (PTA) and sagittal angle (PSA) were measured using the single- and double-line methods (analog nailing, 4.0 mm in diameter) in 160 pairs of C3–C7 pedicles, setting positive and negative values for cranial direction and foot side PSAs, respectively. Comparison of the measured change scope in PTA and PSA between the two methods was carried out; the range was defined as the error range.Results:Significantly, different results (P < 0.05) were obtained between the single- and double-line methods in the error ranges of PTA and PSA in C3–C7 pedicles. Interestingly, the double-line method was better in simulating the actual needs of individualized nailing. The mean values of PTA and PSA were 42.9°, 45.5°, 42.4°, 37.1°, 29.0° and 8.4°, 5.0°, −4.0°, and −7.8°, −8.1°, respectively, with the double-line method.Conclusion:MSCT reconstruction techniques can determine the direction and required parameters for individualized screw placement. In addition, accurate in vivo measurements of PTA and PSA, particularly PSA, provide the orthopedic surgeon with theoretical guidance and reliable basis in screw placement.

A Review of the Historical Evolution, Biomechanical Advantage, Clinical Applications, and Safe Insertion Techniques of Cervical Pedicle Screw Fixation.

Cervical spine instrumentation is evolving with an aim of stabilizing traumatic and non-traumatic cases of the cervical spine with a beneficial reduction, better biomechanical strength, and a strong construct with minimal intraoperative, as well as immediate and late postoperative complications. The evolution from interspinous wiring till cervical pedicle screws has changed the outlook in treating the cervical spine pathologies with maximum 3D stability, decreasing the duration of postoperative immobilization and hospital stay. Some complications associated with the use of cervical pedicle screw can be catastrophic. This review article discusses the morphometry of cervical pedicle; indications, biomechanical superiority, tricks, and pitfalls of cervical pedicle screw; complications and technical advancements in targeting safe surgery; and future directions of cervical pedicle screw instrumentation.

Progress on clinical application of anterior cervical pedicle screw fixation for instable cervical spine disease

Instability of the cervical spine disease requires surgery to restore stability. In the past, surgical methods were divided into two kinds of anterior and posterior. But each has its own disadvantages:anterior vertebral screw has a higher failure rate, sometimes need a second operation; and posterior pedicle screw, lateral mass screw and facet joint screw may make greater trauma, lead to longer hospitalization. For general instable cervical spine disease, according to the location of the disease, only with the anterior or posterior approach can achieve a stable effect. However, it often fails to achieve the desired stability with only anterior or posterior approach for the three column injury of single segment, the disease need for multi-segment corpectomy and discectomy. Meanwhile, combined with the anterior and posterior have more obvious disadvantages:such as prolonged operation time, greater surgical injury, increased risk of infection and so on.In recent years, anterior transpedicular screw (ATPS) as a new technique was used for cervical spine fixation. Its laboratory and clinical studies have been conducted about biomechanical properties, morphological feasibility, pull-out strength, radiological features and new technology for inserting screws. Because of its strong stability, perfect mechanical properties and the satisfactory results of patients, which has been recognized by many scholars. Although this technique has been used in clinical practice, Its long-term clinical effect needs to be further clarified. Even so, the innovative proposal will provide a new thread for the majority of doctors and colleagues in treating unstable cervical disease.