Revisiting the rules for freehand ventriculostomy: a virtual reality analysis

2018 ◽  
Vol 128 (4) ◽  
pp. 1250-1257 ◽  
Author(s):  
Clemens Raabe ◽  
Jens Fichtner ◽  
Jürgen Beck ◽  
Jan Gralla ◽  
Andreas Raabe
Keyword(s):  
Virtual Reality ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Anterior Horn ◽  
Entry Point ◽  
Ct Scans ◽  
Medial Canthus ◽  
Hit Rate ◽  
Entry Points ◽  
Ventricular Puncture

OBJECTIVEFrontal ventriculostomy is one of the most frequent and standardized procedures in neurosurgery. However, many first and subsequent punctures miss the target, and suboptimal placement or misplacement of the catheter is common. The authors therefore reexamined the landmarks and rules to determine the entry point and trajectory with the best hit rate (HtR).METHODSThe authors randomly selected CT scans from their institution’s DICOM pool that had been obtained in 50 patients with normal ventricular and skull anatomy and without ventricular puncture. Using a 5 × 5–cm frontal grid with 25 entry points referenced to the bregma, the authors examined trajectories 1) perpendicular to the skull, 2) toward classic facial landmarks in the coronal and sagittal planes, and 3) toward an idealized target in the middle of the ipsilateral anterior horn (ILAH). Three-dimensional virtual reality ventriculostomies were simulated for these entry points; trajectories and the HtRs were recorded, resulting in an investigation of 8000 different virtual procedures.RESULTSThe best HtR for the ILAH was 86% for an ideal trajectory, 84% for a landmark trajectory, and 83% for a 90° trajectory, but only at specific entry points. The highest HtRs were found for entry points 3 or 4 cm lateral to the midline, but only in combination with a trajectory toward the contralateral canthus; and 1 or 2 cm lateral to the midline, but only paired with a trajectory toward the nasion. The same “pairing” exists for entry points and trajectories in the sagittal plane. For perpendicular (90°) trajectories, the best entry points were at 3–5 cm lateral to the midline and 3 cm anterior to the bregma, or 4 cm lateral to the midline and 2 cm anterior to the bregma.CONCLUSIONSOnly a few entry points offer a chance of a greater than 80% rate of hitting the ILAH, and then only in combination with a specific trajectory. This “pairing” between entry point and trajectory was found both for landmark targeting and for perpendicular trajectories, with very limited variability. Surprisingly, the ipsilateral medial canthus, a commonly reported landmark, had low HtRs, and should not be recommended as a trajectory target.

scholarly journals The Feasibility of Anterior Occipital Condyle Screw for the Reconstruction of Craniovertebral Junction: A Digital Anatomical and Cadaveric Study of a Novel Technique

2020 ◽  
Author(s):  
Dingli Xu ◽  
Haijiao Mao ◽  
Yang Wang ◽  
Kaifeng Gan ◽  
Weihu Ma
Keyword(s):  
Sagittal Plane ◽  
Three Dimensional ◽  
Craniovertebral Junction ◽  
Entry Point ◽  
Ct Scans ◽  
Occipital Condyle ◽  
Novel Technique ◽  
Screw Length ◽  
Mesh Cage ◽  
Technique Apply

Abstract Background: Anterior occipital condyle screw (AOCS) could be a feasible technique apply to the reconstruction of craniovertebral junction. This study was to analyze the feasibility of AOCS.Method: The craniovertebral junction computed tomography (CT) scans of 40 adults were enrolled and imported into Mimics software. Then the three-dimensional reconstruction digital model of craniovertebral junction were established to determine entry point, insertion angle and screw’s trajectory. After AOCS inserted into ten human cadaver spine specimens, CT scans were performed to verify the location between screws and important structures. Result: The optimal entry point is located caudally and medial to the ventral of occipital condyle. The optimal trajectory is in inclination angle (5.9°±3.4°) in the sagittal plane and diverge angle (26.7°±6.0°) in the axial plane with the screw length around 21.6±1.2mm. There were no screws invaded into hypoglossal canal and vertebral artery in all specimens.Conclusion: AOCS fixation is a feasible novel technique for anterior craniovertebral junction reconstruction, and it could be an effective alternative operation for anterior reconstruction with titanium mesh cage.

A radiographic computed tomography–based study to determine the ideal entry point, trajectory, and length for safe fixation using C-2 pars interarticularis screws

2010 ◽  
Vol 12 (6) ◽  
pp. 602-612 ◽  
Author(s):  
Daniel J. Hoh ◽  
Charles Y. Liu ◽  
Michael Y. Wang
Keyword(s):  
Entry Point ◽  
Ct Scans ◽  
Lateral Mass ◽  
Transverse Foramen ◽  
Inferior Aspect ◽  
Significant Difference ◽  
Pars Interarticularis ◽  
Entry Points ◽  
The Mean ◽  
Inferior Edge

Object Effective methods for fixation of the axis include C1–2 transarticular and C-2 pedicle screw placement. Both techniques pose a risk of vertebral artery (VA) injury in patients with narrow pedicles or an enlarged, high-riding VA. Pars screws at C-2 avoid the pedicle, but can cause VA injury with excessively long screws. Therefore, the authors evaluated various entry points and trajectories to determine ideal pars screw lengths that avoid breaching the transverse foramen. Methods Both pars were studied on 50 CT scans (100 total). Various pars lengths were assessed using 2 entry points and 3 trajectories (6 measurements). Entry point A was the superior one-fourth of the lateral mass. Entry point B was 3-mm rostral to the inferior aspect of the lateral mass. Using entry points A and B, Trajectory 1 was the minimum distance to the transverse foramen; Trajectory 2 was the maximum distance to the transverse foramen; and Trajectory 3 was the steepest angle to the pars/C-2 superior facet junction without transverse foramen breach. Results The mean patient age was 46 ± 17 years, and 84% of the CT scans reviewed were obtained in men. There was no significant difference in right or left measurements. Entry point B demonstrated greater pars lengths for each trajectory compared with entry point A (p < 0.0001). For both entry points, Trajectory 3 provided the greatest pars length. Using Trajectory 3 with entry point B, 84, 95, and 99% had a pars length that measured ≥ 18, 16, and 14 mm, respectively. Using Trajectory 3 with Entry point A, only 41, 64, and 87% had a pars length that measured ≥ 18, 16, and 14 mm, respectively. Conclusions Using an entry point 3-mm rostral to the inferior edge of the lateral mass and a trajectory directed toward the superior facet/pars junction, 99% of partes interarticularis in this study would tolerate a 14-mm screw without breach of the transverse foramen.

Anterior lengthening in scoliosis occurs only in the disc and is similar in different types of scoliosis

2021 ◽  
Author(s):  
S de Reuver ◽  
RC Brink ◽  
JF Homans ◽  
L Vavruch ◽  
H Tropp ◽  
...  
Keyword(s):  
Vertebral Body ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Congenital Scoliosis ◽  
Intervertebral Discs ◽  
Ct Scans ◽  
Scoliotic Deformity ◽  
Different Types ◽  
Vertebral Bodies ◽  
Bony Abnormality

Relative anterior spinal overgrowth (RASO) was proposed as a generalized growth disturbance and a potential initiator of adolescent idiopathic scoliosis (AIS). However, anterior lengthening was also observed in neuromuscular (NM) scoliosis, was shown to be restricted to the apical areas and to be located in the intervertebral discs, not in the bone. In this study the goal was to determine if other scoliotic curves of known origin exhibit the similar mechanism of anterior lengthening without changes in the vertebral body. Therefore CT-scans of 18 patients in whom a short segment congenital malformation had led to a long thoracic compensatory curve without bony abnormality were included. Of each vertebral body and intervertebral disc in the compensatory curve, the anterior and posterior length was measured on CT-scans in the exact mid-sagittal plane, corrected for deformity in all three planes. The total AP% of the compensatory curve in congenital scoliosis showed a lordosis (+1.8%) that differed from the kyphosis in non-scoliotic controls (-3.0%; p<0.001), and was comparable to AIS (+1.2%) and NM scoliosis (+0.5%). This anterior lengthening was not located in the bone; the vertebral body AP% showed a kyphosis (-3.2%), similar to non-scoliotic controls (-3.4%), as well as AIS (-2.5%) and NM scoliosis (-4.5%; p=1.000). However, the disc AP% showed a lordosis (+24.3%), which sharply contrasts to the kyphotic discs of controls (-1.5%; p<0.001), but was similar to AIS (+17.5%) and NM scoliosis (+20.5%). The results demonstrate that anterior lengthening is part of the three-dimensional deformity in different types of scoliosis and is exclusively located in the intervertebral discs. The bony vertebral bodies maintain their kyphotic shape, which indicates that there is no active bony overgrowth. Anterior lengthening appears to be a passive result of any scoliotic deformity, rather than being related to the specific cause of AIS.

scholarly journals CT-scan based anatomical study as a guidance for infra-acetabular screw placement

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Quanyi Lu ◽  
Runtao Zhou ◽  
Shichang Gao ◽  
Anlin Liang ◽  
Mingming Yang ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Three Dimensional ◽  
Anatomical Study ◽  
Ischial Tuberosity ◽  
Entry Point ◽  
Screw Placement ◽  
Minimum Thickness ◽  
Males And Females ◽  
The Relationship ◽  
Screw Group

Abstract Background The infra-acetabular corridor is quite narrow, which makes a challenge for the orthopedists to insert the screw. This study aimed to explore the relationship between the infra-acetabular corridor diameter (IACD) and the minimum thickness of medial acetabular wall (MTMAW), and to clarify the way of screw placement. Methods The Computed tomography (CT) data of 100 normal adult pelvises (50 males and 50 females respectively) were collected and pelvis three-dimensional (3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabulum was carried out orienting from iliopubic eminence to ischial tuberosity and the IACD was measured by placing virtual screws which was vertical to the corridor transverse section of “teardrop”. The relationship between IACD and MTMAW was analyzed. When IACD was ≥5 mm, 3.5 mm all-in screws were placed. When IACD was < 5 mm, 3.5 mm in-out-in screws were placed. Results The IACD of males and females were (6.15 ± 1.24) mm and (5.42 ± 1.01) mm and the MTMAW in males and females were (4.40 ± 1.23) mm and (3.60 ± 0.81) mm respectively. The IACD and MTMAW in males were significantly wider than those of females (P < 0.05), and IACD was positively correlated with MTMAW (r = 0.859), the regression equation was IACD = 2.111 + 0.917 MTMAW. In the all-in screw group, 38 cases (76%) were males and 33 cases (66%) were females respectively. The entry point was located at posteromedial of the apex of iliopubic eminence, and the posterior distance and medial distance were (8.03 ± 2.01) mm and (8.49 ± 2.68) mm respectively in males. As for females, those were (8.68 ± 2.35) mm and (8.87 ± 2.79) mm respectively. In the in-out-in screw group, 12 cases (24%) were males and 17 cases (34%) were females, respectively. The posterior distance and medial distance between the entry point and the apex of iliopubic eminence were (10.49 ± 2.58) mm and (6.17 ± 1.84) mm respectively in males. As for females, those were (10.10 ± 2.63) mm and (6.63 ± 1.49) mm respectively. The angle between the infra-acetabular screw and the sagittal plane was medial inclination (0.42 ± 6.49) °in males, lateral inclination (8.09 ± 6.33) °in females, and the angle between the infra-acetabular screw and the coronal plane was posterior inclination (54.06 ± 7.37) °. Conclusions The placement mode of the infra-acetabular screw (IAS) can be determined preoperatively by measuring the MTMAW in the CT axial layers. Compared with all-in screw, the in-out-in screw entry point was around 2 mm outwards and backwards, and closer to true pelvic rim.

scholarly journals Three-dimensional assessment of unilateral subcondylar fracture using computed tomography after open reduction

2014 ◽  
Vol 47 (02) ◽  
pp. 203-209 ◽  
Author(s):  
Sathya Kumar Devireddy ◽  
R. V. Kishore Kumar ◽  
Rajasekhar Gali ◽  
Sridhar Reddy Kanubaddy ◽  
Mallikarjuna Rao Dasari ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Statistical Difference ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Mandibular Condyle ◽  
Clinical Results ◽  
Considerable Change ◽  
Ct Scans ◽  
Open Method ◽  
Condylar Fractures

ABSTRACT Objective: The aim was to assess the accuracy of three-dimensional anatomical reductions achieved by open method of treatment in cases of displaced unilateral mandibular subcondylar fractures using preoperative (pre op) and postoperative (post op) computed tomography (CT) scans. Materials and Methods: In this prospective study, 10 patients with unilateral sub condylar fractures confirmed by an orthopantomogram were included. A pre op and post op CT after 1 week of surgical procedure was taken in axial, coronal and sagittal plane along with three-dimensional reconstruction. Standard anatomical parameters, which undergo changes due to fractures of the mandibular condyle were measured in pre and post op CT scans in three planes and statistically analysed for the accuracy of the reduction comparing the following variables: (a) Pre op fractured and nonfractured side (b) post op fractured and nonfractured side (c) pre op fractured and post op fractured side. P <; 0.05 was considered as significant. Results: Three-dimensional anatomical reduction was possible in 9 out of 10 cases (90%). The statistical analysis of each parameter in three variables revealed (P <; 0.05) that there was a gross change in the dimensions of the parameters obtained in pre op fractured and nonfractured side. When these parameters were assessed in post op CT for the three variables there was no statistical difference between the post op fractured side and non fractured side. The same parameters were analysed for the three variables in pre op fractured and post op fractured side and found significant statistical difference suggesting a considerable change in the dimensions of the fractured side post operatively. Conclusion: The statistical and clinical results in our study emphasised that it is possible to fix the condyle in three-dimensional anatomical positions with open method of treatment and avoid post op degenerative joint changes. CT is the ideal imaging tool and should be used on a regular basis for cases of condylar fractures.

scholarly journals How to choose infra-acetabular screw? Option of All-In or In-Out-in Screw Based on Computed Tomography Measurement of Infra-Acetabular Corridor

2021 ◽  
Author(s):  
Quanyi Lu ◽  
Runtao Zhou ◽  
Shichang Gao ◽  
Anlin Liang ◽  
Mingming Yang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Ischial Tuberosity ◽  
Entry Point ◽  
Minimum Thickness ◽  
Males And Females ◽  
Ct Data ◽  
The Relationship ◽  
Screw Group

Abstract Background: The infra-acetabular corridor is quite narrow, which makes a challenge for the orthopedists to insert the screw. This study aimed to explore the relationship between the infra-acetabular corridor diameter (IACD) and the minimum thickness of medial acetabular wall(MTMAW), and to clarify the way of screw placement. Methods: The Computed tomography (CT) data of 100 normal adult pelvises (50 males and 50 females respectively) were collected and pelvis three-dimensional(3D) reconstruction was performed by using Mimics software and the 3D model was imported into Geomagic Studio software. The perspective of acetabulum was carried out orienting from iliopubic eminence to ischial tuberosity and the IACD was measured by placing virtual screws which was vertical to the corridor transverse section of "teardrop". The relationship between IACD and MTMAW was analyzed. When IACD was ≥ 5 mm, 3.5mm all-in screws were placed. When IACD was < 5 mm, 3.5mm in-out-in screws were placed. Results: The IACD of males and females were (6.15 ± 1.24) mm and (5.42 ± 1.01) mm and the MTMAW in males and females were (4.40 ± 1.23) mm and (3.60 ± 0.81)mm respectively. The IACD and MTMAW in males were significantly wider than those of females (P < 0.05), and IACD was positively correlated with MTMAW (r = 0.859), the regression equation was IACD = 2.111 + 0.917 MTMAW. In the all-in screw group, 38 cases (76%) were males and 33 cases (66%) were females respectively. The entry point was located at posteromedial of the apex of iliopubic eminence, and the posterior distance and medial distance were (8.03±2.01)mm and (8.49±2.68)mm respectively in males. As for females, those were (8.68±2.35)mm and (8.87±2.79)mm respectively. In the in-out-in screw group, 12 cases (24%) were males and 17 cases (34%) were females, respectively. The posterior distance and medial distance between the entry point and the apex of iliopubic eminence were (10.49±2.58)mm and (6.17±1.84)mm respectively in males. As for females, those were (10.10±2.63)mm and (6.63±1.49)mm respectively. The angle between the infra-acetabular screw and the sagittal plane was medial inclination (0.42 ± 6.49) °in males, lateral inclination (8.09 ± 6.33) °in females, and the angle between the infra-acetabular screw and the coronal plane was posterior inclination (54.06 ± 7.37) °. Conclusions: The placement mode of the infra-acetabular screw(IAS) can be determined preoperatively by measuring the MTMAW in the CT axial layers. Compared with all-in screw, the in-out-in screw entry point was around 2mm outwards and backwards, and closer to true pelvic rim.

scholarly journals Subtalar Nonunion Following Tibiotalocalcaneal Fusion Using an Intramedullary Nail: A Case Series of Errant Entry Points

2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0029
Author(s):  
Anthony Martella ◽  
Ruixian Yue ◽  
Michael Boin ◽  
Jonathan Rogozinski ◽  
Trenden Flanigan ◽  
...  
Keyword(s):  
Intraoperative Imaging ◽  
Case Series ◽  
Valgus Deformity ◽  
Entry Point ◽  
Medial Wall ◽  
Ct Scans ◽  
Patient Demographics ◽  
Entry Points ◽  
Hindfoot Deformity ◽  
Valgus Alignment

Category: Hindfoot Introduction/Purpose: Tibiotalocalcaneal (TTC) arthrodesis is a procedure used to treat hindfoot deformity and/or arthritis. Retrograde intramedullary nails have been used as a method of fixation. The nails are either straight or have a bend to accommodate valgus alignment of the hindfoot. Studies comparing nail types or analysis of nonunions are lacking in the available literature on the subject despite a reported nonunion rate of up to 20%. The purpose of this study was to report a series of subtalar nonunions that all had an entry point that was too medial on the calcaneus resulting in inadequate purchase of the nail in the calcaneus. Methods: Six cases of subtalar nonunion were retrospectively reviewed. All were referred for second opinion. Evaluation consisted of examination, radiographs and CT scans. Patient demographics, comorbidities and findings common to all cases were recorded. Results: Presenting complaints in all cases were persistent swelling. Non-neuropathic cases all had hindfoot pain. In this series, all the implants were straight nails. Radiographs and CT scans revealed that all cases were done for severe valgus deformity with subtalar subluxation. In each of the cases, the deformity was under corrected and the nail entry point was too medial on the calcaneus which resulted in reaming out the medial wall of the calcaneus, decreasing the amount of fixation obtained with the nail. In each of the cases, the medial wall of the calcaneus was deficient and the nail had no medial containment. Conclusion: Severe valgus deformity with subtalar subluxation is a risk factor for subtalar nonunion when the deformity is under corrected and a straight nail is used. Ensuring that the tibia talus and calcaneus are collinear and that the entry point in the calcaneus is sufficiently lateral are important factors to consider when addressing this type of deformity. Accurate intraoperative imaging is essential to ensure proper positioning of the entry point to avoid reaming out the medial wall of the calcaneus and to ensure adequate purchase of the nail in the calcaneus.

scholarly journals Comparative analysis of endoscopic third ventriculostomy trajectories in pediatric cases

2015 ◽  
Vol 16 (6) ◽  
pp. 626-632 ◽  
Author(s):  
Zsolt Zador ◽  
David J. Coope ◽  
Ian D. Kamaly-Asl
Keyword(s):  
Endoscopic Third Ventriculostomy ◽  
Obstructive Hydrocephalus ◽  
Three Dimensional ◽  
Internal Capsule ◽  
Entry Point ◽  
Third Ventriculostomy ◽  
Frontal Horn ◽  
Entry Points ◽  
Mri Scans ◽  
Ventricle Size

OBJECT Endoscopic third ventriculostomy (ETV) has become a widely used method for CSF diversion when treating obstructive hydrocephalus. There are multiple recommendations on the transcortical ETV entry points, and some are specifically designed to provide a trajectory that avoids displacement to the eloquent periventricular structures. However, the morphology of the ventricular system is highly variable in hydrocephalus, and therefore a single best ETV trajectory may not be applicable to all cases. In the current study, 3 frequently quoted ETV entry points are compared in a cohort of pediatric cases with different degrees of ventriculomegaly. METHODS The images of 30 consecutive pediatric patients with varying degrees of ventriculomegaly were reviewed. Three-dimensional models were created using radiological analysis of anatomical detail and preoperative MRI scans in order to simulate 3 frequently quoted ETV trajectories for rigid neuroendoscopes. These trajectories were characterized based on the frequency and depth of tissue displacement to structures such as the fornix, caudate nucleus, genu of the internal capsule, and thalamus. The results are stratified based on ventricle size using the frontal horn ratio (FHR). RESULTS Eloquent areas were displaced in nearly all analyzed entry points (97%–100%). Stratifying the data based on ventricle size revealed that 1) lateral structures were more likely to be displaced in cases of intermediate ventriculomegaly (FHR < 0.4) using all 3 trajectories, whereas 2) the fornix was less likely to be displaced using more posteriorly placed trajectories for severe ventriculomegaly (FHR > 0.4). Allowing for minimal (2.4 mm) tissue displacement, a more posterior entry point was less traumatic for severe ventriculomegaly. CONCLUSIONS There is no single best ETV trajectory that fully avoids displacement of the eloquent periventricular structures. Larger ventricles require a more posteriorly placed entry point in order to reduce injury to the eloquent structures, and intermediate ventricles would dictate a medial entry point. These results suggest that the optimal entry point should be selected on a case-by-case basis after incorporating ventricle size.

scholarly journals The Use of Virtual Reality in the Teaching of Challenging Concepts in Virology, Cell Culture and Molecular Biology

2021 ◽  
Vol 2 ◽  
Author(s):  
F. Jerry Reen ◽  
Owen Jump ◽  
Brian P. McSharry ◽  
John Morgan ◽  
David Murphy ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Molecular Biology ◽  
Teaching And Learning ◽  
Three Dimensional ◽  
Learning Approaches ◽  
Face To Face ◽  
Gene Therapies ◽  
Online Engagement ◽  
Entry Points ◽  
Biotechnology Sector

The rapidly expanding biotechnology sector horizon is expected to create a surge in demand for expertise underpinning cell and gene therapies, which are recognized as the next generation of medicines. New and innovative approaches to implement active and performative learning in the Molecular Life Sciences are required to support this and to address limitations associated with traditional “front of class” lectern delivery of challenging, three dimensional molecular concepts. Therefore, an immediate need exists for the development and implementation of immersive learning approaches in Virology, Cellular Sciences and Molecular Biology to underpin sustainable development of graduate students for academic and industrial research careers. The Covid-19 pandemic has led to significant changes in the delivery of education globally, with online engagement and accelerated uptake of novel teaching and assessment modalities into majority practice within institutions. This development has been driven by externally imposed necessity and it remains to be seen what form teaching and learning will take post-Covid. Irrespective of the pandemic, technologies are available which can serve intrinsically motivated, discipline specific shifts toward enhanced learner experiences and learning outcomes. Immersive virtual reality offers one such approach to open new entry points for student learning of abstract molecular concepts, which will be just as relevant upon our return to face-to-face teaching. Key to delivering this will be engagement and collaboration by disciplinary and technical experts. Here, we discuss global advances in the area of VR and Molecular Science education and assess potential paths forward for teaching and learning impact and innovative education.

scholarly journals Computer-assisted subcapital correction osteotomy in slipped capital femoral epiphysis using individualized drill templates

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Sima Zakani ◽  
Christopher Chapman ◽  
Adam Saule ◽  
Anthony Cooper ◽  
Kishore Mulpuri ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Slipped Capital Femoral Epiphysis ◽  
Three Dimensional ◽  
Hip Dislocation ◽  
Accurate Method ◽  
Entry Point ◽  
Computer Assisted ◽  
X Rays ◽  
Direct Benefits ◽  
Entry Points

Abstract Background Subcapital osteotomy by means of surgical hip dislocation is a treatment approach offered for moderate-to-severe cases of Slipped Capital Femoral Epiphysis (SCFE). This procedure is demanding, highly dependent on the surgeon’s experience, and requires considerable radiation exposure for monitoring and securing the spatial alignment of the femoral head. We propose the use of individualized drill guides as an accurate method for placing K-wires during subcapital correction osteotomies in SCFE patients. Methods Five CT scans of the hip joint from otherwise healthy patients with moderate-to-severe SCFE were selected (ages 11–14). Three dimensional models of each patient’s femur were reconstructed by manual segmentation and physically replicated using additive manufacturing techniques. Five orthopaedic surgeons virtually identified the optimal entry point and direction of the two threaded wires for each case. 3D printed drill guides were designed specific to each surgical plan, with one side shaped to fit the patient’s bone and the other side containing holes to guide the surgical drill. Each surgeon performed three guided (using the drill guides) and three conventional (freehand) simulated procedures on each case. Each femur model was laser scanned and digitally matched to the preoperative model for evaluation of entry points and wire angulations. We compared wire entry point, wire angulation, procedure time and number of x-rays between guided and freehand simulated surgeries. Results The guided group (1.4 ± 0.9 mm; 2.5° ± 1.4°) was significantly more accurate than the freehand group (5.8 ± 3.2 mm; 5.3° ± 4.4°) for wire entry location and angulation (p < 0.001). Guided surgeries required significantly less drilling time and intraoperative x-rays (90.5 ± 42.2 s, 3 ± 1 scans) compared to the conventional surgeries (246.8 ± 122.1 s, 14 ± 5 scans) (p < 0.001). Conclusions We conclude that CT-based preoperative planning and intraoperative navigation using individualized drill guides allow for improved accuracy of wires, reduced operative time and less radiation exposure in simulated hips. Clinical relevance This preliminary study shows promising results, suggesting potential direct benefits to SCFE patients by necessitating less time under anesthesia and less intra-operative radiation exposure to patients, and increasing surgical accuracy.

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