Free hand technique of cervical lateral mass screw fixation.
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ABSTRACT:
SUBMITTER: Eldin MM
PROVIDER: S-EPMC5490344 | biostudies-other | 2017 Apr-Jun
REPOSITORIES: biostudies-other
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Project description:Introduction The cervical spine is a highly mobile segment of the spinal column, liable to a variety of diseases and susceptible to trauma. It is a complex region where many vital structures lie in close proximity. Lateral mass screw fixation has become the method of choice in stabilizing subaxial cervical spine among other posterior cervical fixation techniques whenever the posterior elements are absent or compromised. Objective This study examined cervical specimens of cadavers and cervical computed tomography (CT) scans to minimize as much as possible complications of cervical lateral mass screw placement such as vertebral artery or nerve root injuries, facet joint violations, or inadequate placement. Methods Forty normal cervical CT scans, obtained from the emergency unit as part of the trauma workup, were included in this study plus 10 cervical cadaveric specimens obtained from the Alexandria Neuro-anatomy laboratory. There were three fixed parameters for screw insertion in this study. First, the point of screw insertion was the midpoint of the lateral mass; it was the crossing point between the sagittal and axial planes of the posterior cortex of the lateral mass. Second, the direction of the screw in the craniocaudal plane was 30 degrees cranially to avoid facet joint penetration. Third, the exit point of the screw was located on the ventral cortex of the lateral mass just lateral to the root of the transverse process in the midaxial cut of each lateral mass, to make a sound bicortical fixation without injuring the vertebral artery or the nerve root. The selected screw trajectory in this study was the line drawn between the inlet and exit points. The depth and width of the lateral mass of the cervical vertebrae from C3 to C7 were measured as well as the angle of screw trajectory from the sagittal plane. All these measures were applied on the cadaveric specimens to make sure that no injury to the vertebral artery, nerve root, or facet joint occurred. Results As regards the collected measurements of the lateral mass of all subaxial cervical vertebrae, the study revealed that the average depth of the lateral mass was 12.83 ± 1.28 mm. The average width of the lateral mass was 11.92 ± 0.96 mm. The average divergent angle of bicortical screw insertion without injury to the vertebral artery or the nerve root was 19.51 ± 1.83 degrees. As regard the cadaveric specimens, based on all the collected measurements taken from the CT scans, there was no reported injury to the vertebral arteries or nerve roots or penetration to the facet joints. Conclusion Lateral mass fixation can be applied easily and safely for all levels of subaxial cervical spine from C3 to C6 with the following parameters: (1) the point of entry is the midpoint of the lateral mass; (2) the screw trajectory is directed 30 degrees cranially and 20 degrees laterally; (3) the screw length is 13 to 15 mm.
| S-EPMC3864406 | biostudies-other
Project description:We sought to compare the safety and accuracy of a new free-hand pedicle screw placement technique to that of the conventional technique. One hundred fifty-three consecutive adult patients with simple fracture in the thoracic or/and lumbar spine were alternately assigned to either the new free-hand or the conventional group. In the new free-hand technique group, preoperative computerized tomography (CT) images were used to calculate the targeted medial-lateral angle of each pedicle trajectory and the pedicle screw was inserted perpendicular to the correspond-ing supraspinal ligament. In the conventional technique group, the medial-lateral and cranial-caudal angle of each pedicle trajectory was determined by intraoperatively under fluoroscopic guidance. The accuracy rate of pedicle screw placement, the time of intraoperative fluoroscopy, the operating time and the amount of blood loss during operation were respectively compared. All screws were analyzed by using intraoperative radiographs, intraoperative triggered electromyography (EMG) monitoring data, postoperative CT data and clinical outcomes. The accuracy rate of pedicle screw placement in the new free-hand technique group and the conventional technique group was 96.3% and 94.2% (P < 0.05), respectively. The intraoperative fluoroscopy time of the new technique group was less than that of the conventional technique group (5.37 seconds vs. 8.79 seconds, P < 0.05). However, there was no statistical difference in the operating time and the amount of blood loss during operation (P > 0.05). Pedicle screw placement with the free-hand technique which keeps the screw perpendicular to the supraspinal ligament is an accurate, reliable and safe technique to treat simple fracture in the thoracic or lumbar spine.
| S-EPMC3904177 | biostudies-literature
Project description:An os acetabuli (OA) increases the contact area and surface area of the acetabulum and is important to maintain congruity of the hip joint. Thus preservation of this ossicle is important to prevent loss of contact area and ensure containment of the femoral head. We describe an all-arthroscopic approach to the fixation of OA with a compression screw. Initially, the fibrous tissue is debrided between the acetabular rim and the OA, a guidewire is placed through the OA up to the acetabular rim, and a screw is inserted over the wire. Compression of the OA is achieved with bone-to-bone contact. This technique prevents loss of femoral head coverage, reducing the risk of subluxation and subsequent osteoarthritis.
| S-EPMC5495954 | biostudies-literature
Project description:Transverse glenoid fractures with a cranial coracoglenoidal fragment (Ideberg type III) can lead to detrimental post-traumatic sequelae. Open surgery requires an extensive surgical approach. Arthroscopic procedures are highly challenging with respect to both fracture reduction and screw osteosynthesis. We present a reproducible arthroscopic technique for a dislocated transverse glenoid fracture using 5 standard portals. Grasping the coracoid with a small, serrated reduction clamp through the anterior portal allows simple and sufficient reduction. Safe screw osteosynthesis can then be performed from cranially without the need to create a Neviaser portal.
| S-EPMC8626685 | biostudies-literature
Project description:Although several surgical techniques have been described to perform meniscal allograft transplantation with good clinical results and although different methods of capsular stabilization can be found in the literature, there is no standard surgical technique to prevent a common complication in the most of series: the tendency to a radial displacement or extrusion of the transplanted menisci. We present a simple, reproducible, and implant-free technique to perform a lateral capsular fixation (capsulodesis) at the time of only the soft-tissue fixation technique of meniscal allograft transplantation in an effort to reduce or prevent the risk of graft extrusion. Using a minimum of two 2.4-mm tunnels drilled from the contralateral side of the tibia with the help of a regular tibial anterior cruciate ligament guide, a capsular attachment to the lateral tibial plateau is obtained.
| S-EPMC5442305 | biostudies-literature
Project description:The os acetabuli is thought to arise from unfused secondary ossification centers or as rim fractures in the setting of dysplastic hips or hips with femoroacetabular impingement. Resection of a large os acetabuli can lead to structural instability of the joint, and in these cases, osteoplasty of the impingement, reduction and internal fixation of the osseous fragment, and labral repair have been described in the literature. Anchor fixation for labral repair in the surrounding zone of the osteosynthesis might bring some technical problems. We aim to describe a technical modification improving labral lesion treatment while addressing the rim fracture. The addition of a suture to the screw addresses both lesions because it simultaneously has the function of a screw and an anchor. A suture-on-screw technique for os acetabuli fixation helps surgeons to gain versatility and is more cost-effective for the patients and health services.
| S-EPMC5368258 | biostudies-literature
Project description:BACKGROUND:Posterior 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. METHODS:A 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. RESULTS:Overall, 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. CONCLUSIONS:With 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.
| S-EPMC7681976 | biostudies-literature
Project description:STUDY DESIGN:Retrospective case series. OBJECTIVE:To describe a modified technique for mini-open transforaminal lumbar interbody fusion (TLIF) that improves visualization for decompression, fusion, and freehand pedicle screw insertion. Accuracy of freehand pedicle screw placement with this technique was assessed. SUMMARY OF BACKGROUND DATA:Mini-open TLIF is a minimally invasive technique that allows limited visualization of the bone and neural anatomy via an expandable tubular retractor inserted through the Wiltse plane. No significant modification that of this technique has been described in detail. METHODS:In this study, 92 consecutive patients underwent one-level modified mini-open TLIF (MOTLIF). MOTLIF modifications consisted of (i) transmuscular dissection through the multifidus muscle rather than intermuscular dissection in the Wiltse plane; (ii) microsurgical detachment of multifidus from the facet rather than muscle dilation; (iii) en bloc total facetectomy (unilateral or bilateral, as needed for decompression); (iv) facet autograft used for interbody fusion; and (v) solid pedicle screws placed bilaterally by a freehand technique under direct vision. RESULTS:The mean age was 53 years. Mean follow-up was 35 months (minimum 2 yrs). By 6 months, mean Visual Analog Scale for back and leg pain had improved from 51 to 19 and from 58 to 17, respectively, and mean Oswestry Disability Index (ODI) improved from 53 to 16. These improvements persisted at 2 years. Solid fusion, defined by computed tomography at 1 year, was achieved in 88.1%, whereas satisfactory fusion was achieved in 95.2% of patients. Pedicle screws were accurately placed in 335 of 336 imaged pedicles (pedicle breach grades: 91.1% grade 1; 8.6% grade 2; and 0.3% grade 3). Mean fluoroscopy time was 29.3?seconds. CONCLUSION:MOTLIF is a safe and effective minimally invasive technique with a high fusion rate. It allows accurate pedicle screw placement by a freehand technique. By eliminating bi-planar fluoroscopy, it helps reduce radiation exposure. This is the largest published report of mini-open TLIF to date. LEVEL OF EVIDENCE:4.
| S-EPMC5001135 | biostudies-literature
Project description:Os acetabuli is thought to be the result of an unfused ossification center or an acetabular rim fracture in the setting of femoral-sided femoroacetabular impingement syndrome. Historically, patients with symptomatic hips have been treated with resection alone; however, in patients with large bone fragments or with reduced acetabular coverage prior to surgical intervention, iatrogenic dysplasia and structural instability may develop after resection. Therefore, for patients with an acetabular os, labral tearing, and cam-type femoroacetabular impingement, internal fixation of the os acetabuli, femoral osteochondroplasty, and labral repair have been described. We propose a "suture-on-screw" arthroscopic technique to simultaneously address both the labral tear and os acetabuli, thereby reducing the number of suture anchors required for labral fixation, leading to an efficient and cost-effective approach for the treatment of these patients.
| S-EPMC8252835 | biostudies-literature
Project description:Study designSingle-center retrospective case series.ObjectiveThe purpose of this study was to assess the safety and accuracy of three-dimensional (3D)-printed individualized drill guides for pedicle and lateral mass screw insertion in the cervical and upper-thoracic region, by comparing the preoperative 3D surgical plan with the postoperative results.Summary of background dataPosterior spinal fusion surgery can provide rigid intervertebral fixation but screw misplacement involves a high risk of neurovascular injury. However, modern spine surgeons now have tools such as virtual surgical planning and 3D-printed drill guides to facilitate spinal screw insertion.MethodsA total of 15 patients who underwent posterior spinal fusion surgery involving patient-specific 3D-printed drill guides were included in this study. After segmentation of bone and screws, the postoperative models were superimposed onto the preoperative surgical plan. The accuracy of the realized screw trajectories was quantified by measuring the entry point and angular deviation.ResultsThe 3D deviation analysis showed that the entry point and angular deviation over all 76 screw trajectories were 1.40 ± 0.81 mm and 6.70 ± 3.77°, respectively. Angular deviation was significantly higher in the sagittal plane than in the axial plane (P = 0.02). All screw positions were classified as "safe" (100%), showing no neurovascular injury, facet joint violation, or violation of the pedicle wall.Conclusions3D virtual planning and 3D-printed patient-specific drill guides appear to be safe and accurate for pedicle and lateral mass screw insertion in the cervical and upper-thoracic spine. The quantitative 3D deviation analyses confirmed that screw positions were accurate with respect to the 3D-surgical plan.Level of Evidence: 4.
| S-EPMC7787187 | biostudies-literature