|Year : 2021 | Volume
| Issue : 4 | Page : 220-225
Feasibility and adaptation of three-dimensional model for surgical planning and training: A pilot study
Binita Chaudhary1, Utpal Anand2, Veena Kumari3, Prabhat Agrawal4, Prem Kumar5, Rajeev Nayan Priyadarshi6
1 Assistant Professor, Department of Anatomy, All India Institute of Medical Sciences, Patna, Bihar, India
2 Associate Professor, Department of Surgical Gastroenterology, All India Institute of Medical Sciences, Patna, Bihar, India
3 Additional Professor, Department of Burns and Plastic surgery, All India Institute of Medical Sciences, Patna, Bihar, India
4 Assistant Professor, Department of Orthopaedics, All India Institute of Medical Sciences, Patna, Bihar, India
5 Professor, Department of Radio-Diagnosis, All India Institute of Medical Sciences, Patna, Bihar, India
6 Additional Professor, Department of Radio-Diagnosis, All India Institute of Medical Sciences, Patna, Bihar, India
|Date of Submission||02-Sep-2021|
|Date of Decision||03-Oct-2021|
|Date of Acceptance||18-Oct-2021|
|Date of Web Publication||28-Oct-2021|
Department of Anatomy, All India Institute of Medical Sciences, Phulwari Sharif, Patna, - 801 507, Bihar
Source of Support: None, Conflict of Interest: None
Background: Three dimensional (3D) printing can produce accurate anatomical model of any part of the body. This study is based on reconstruction of models of the affected body part for preoperative planning and to see its usefulness in training of resident doctors and for patient education. Methodology: Thirty surgically operated patients were retrospectively reviewed and were divided into the conventional planning group (n = 14) and planning with 3D printing group (n = 16). Pathological structures from clinical cases were identified on multidetector computed tomography images and were then transferred to Dicom to print software and saved in a standard format digital imaging and communication in medicine. Segmented regions were combined to create 3D models. Printout of models was taken after being edited by Geomagic free form plus software. Models prepared using 3D printing technology were used to simulate the real surgical operation. The models were used by surgeons for surgical planning and to train their resident doctors. Surgical duration and blood loss were recorded during operation. A questionnaire was provided to the surgeons and residents to assess the utility of 3D models in pre-surgical planning. Results: The mean surgical time in planning with the 3D printing group and conventional planning group was 129.090 ± 36.79 min and 218 ± 94.932 min (P < 0.05). The intraoperative blood loss in planning with 3D printing group and conventional planning group was 130 ± 69.019 ml and (455 ± 44.122 ml) (P < 0.05). Forty subjects completed the survey. Twenty-nine (96.66%) surgeons gave favorable responses (80% found it to be very helpful and 16% helpful) when asked about the utility of these models in the visualization of abnormal pathological anatomy and preoperative planning. Conclusion: Our study suggests that 3D printing technology is useful to aid to surgical planning and provides teaching materials for residents in learning surgery.
Keywords: Anatomical models, computed tomography, three-dimensional image
|How to cite this article:|
Chaudhary B, Anand U, Kumari V, Agrawal P, Kumar P, Priyadarshi RN. Feasibility and adaptation of three-dimensional model for surgical planning and training: A pilot study. Natl J Clin Anat 2021;10:220-5
|How to cite this URL:|
Chaudhary B, Anand U, Kumari V, Agrawal P, Kumar P, Priyadarshi RN. Feasibility and adaptation of three-dimensional model for surgical planning and training: A pilot study. Natl J Clin Anat [serial online] 2021 [cited 2021 Dec 8];10:220-5. Available from: http://www.njca.info/text.asp?2021/10/4/220/329493
| Introduction|| |
The correct interpretation of anatomy is crucial in surgical planning and optimizing surgical results. For this reason, advanced imaging techniques such as multi-detector computed tomography (MDCT) are used for preoperative evaluation. These latest imaging techniques are capable of generating large volumetric data that can produce images in any desired planes (multi-planner imaging). It can also produce three-dimensional (3D) images, but visualization of 3D images in flat screen does not give depth and tactile perception.
Three-dimensional printing (3DP) is a novel technique that can generate 3D solid models from MDCT. As the 3D models obtained by this technology are almost the exact replicas of human body parts, it can help medical professionals to understand the normal anatomy and to interpret the pathological conditions.
3D printed models have been used by some researchers for learning gross anatomy whereas others used the models to understand neuroanatomy and the dynamic developmental changes of embryology.,,,, Furthermore, with the inclusion of 3DP technology, liver resection, and maxillofacial surgery has advanced., According to Shen et al., preoperative simulation using a 3D printing model is helpful for the treatment of old and complex fractures. It may be conducive to preoperative planning and can make surgical procedures accurate. According to Powers et al., 3DP in the field of medicine is growing quickly, and will soon be incorporated into the way residents are taught and educated. Models prepared by 3D printing may prove to be a valuable resource to urology trainees. It may influence both trainees and patients' understanding of renal malignancy., However, the studies are small and researchers have done the study pertinent to a particular surgical discipline. The aim of the study was to investigate the feasibility of 3D model in the planning of surgery to improve the surgical outcome (i.e., surgical time and blood loss). The study further examines the usefulness of 3D models in training resident doctors in a medical institution.
| Materials and Methods|| |
Study design and patients
This retrospective study was performed in the Department of Anatomy to determine the utility of 3D printed model for surgical planning and training of resident doctors. 30 patients were enrolled who underwent operation from August 2019 to March 2020. According to the method of planning, patients were divided into conventional planning group (n = 14) and planning with 3D printing group (n = 16). In the conventional planning group, the preoperative planning was based on computed tomography (CT) imaging; whereas in planning with 3D printing group preoperative planning was based on the 3D printed model. There were no significant differences in both groups in terms of demographic data and choice of surgical approach. The study was approved by Institutional Ethical Committee (IEC/2020/506). Anonymized DICOM data was used to preserve patient confidentiality.
The radiographic images
MDCT imaging were retrospectively reviewed with the help of radiologist. CT scan included images in axial, coronal, and sagittal planes. The underlying pathology was identified including the anatomical landmarks and blood vessels.
The Images from CT were then transferred to D2P software (Dicom to print software Version 18.104.22.1683, 3D system, USA) and saved in a standard DICOM format (i.e., digital imaging and communication in medicine). Bone, soft tissue, blood vessels, and other anatomical features were semi-automatically segmented into separate areas. Segmented regions were then combined to create a 3D object. These 3D objects were exported from D2P as Standard Tessellation Language (STL) files. STL files were repaired, smoothened, and edited in 3D design software (Geomagic freeform plus, 3D system) and a virtual 3D prototype was created. 3D models were printed with Project color jet printing (CJP) technology using gypsum. The 3D printer used was Projet 860 Pro, 3DS, USA. The models were used by the surgeon for planning the surgery (i.e., rehearsal were done before final operation) and training their resident doctors (practising the surgical steps). [Figure 1] shows the outline for the study.
The assessment parameters (variables) included in the study were surgical time (time for skin incision to closure), blood loss (blood collected in suction bottle and from weighed gauge), and complications (fever, delayed wound healing).
Administration of study questionnaire/survey
A questionnaire was provided to the operating surgeons and resident doctors to see the usefulness of 3D models. The questionnaire was prepared by discussion among researchers and had close-ended questions (yes/no type response). Before administration of the questionnaire, reliability was tested and it was prevalidated. An analysis of the reliability of the questionnaire had a Cronbach's α of 0.7. The salient points of the questionnaire were: Whether the patient-specific 3D printed models were useful for presurgical planning or not? Did the presurgical planning affected the final operative time (increase or decrease in operating time)? Did any complications occur? Was postoperative revision surgery required? Whether the 3D model helped them to understand surgical anatomy?
The quantitative data obtained during the research were statistically analyzed through Microsoft excel software (2013 Version) and statistical package R Version 4.1.1. Qualitative data are represented as numbers and percentages, whereas quantitative data are represented by mean and standard deviation. The normality of distribution for continuous numeric variables was assessed using Shapiro-Wilk test. Chi-square test was used for qualitative data. Independent t-test was used for normally distributed data otherwise MannWhitney test was used. P < 0.05 was considered to be significant.
| Results|| |
In the conventional planning group of 14 patients (11 males and 3 females), the mean age of patients was 12 ± 9.606 years and body mass index (BMI) 18.649 ± 5.49. In planning with the 3D printing group, there were 16 patients (10 males and 6 females) with the mean age of 19.09 ± 5.53 years; BMI was 18.84 ± 1.353.
The mean surgical time in planning with the 3D printing group was 129.090 ± 36.79 min which was significantly lower (P < 0.05) than the conventional planning group (218 ± 94.932 min).
The intraoperative blood loss in planning with the 3D printing group (130 ± 69.019 ml) was significantly less than that in the conventional planning group (455 ± 44.122 ml) (P < 0.05).
The rate of complication (delayed wound healing) in planning with 3D printing group and the conventional group was 6.25% (1/16) and 14.28% (2/14) respectively.
The most frequent clinical indications were spine deformity, cleft palate, temporomandibular joint (TMJ) ankyloses, traumatic fracture, maxilla and zygomatic bone, mandible, Porto-systemic shunt surgery [Table 1].
|Table 1: Clinical indications for reconstruction of three dimensional models for preoperative planning by different surgical specialities|
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Scoliosis model of the spine was developed from MDCT data of the patient to assess the lateral bending and rotation of the thoracic spine. The 3D model helped in the localization of the point of maximum convexity which helped the surgeons to define the deviation of the spine from the normal anatomy [Figure 2]. Osteotomy of the vertebra and requirement of graft were preplanned in the model before the final surgery.
|Figure 2: Axial computed tomography image of scoliosis (a), three dimensional-reconstructed image of spine showing point of maximum convexity. Osteotomy was planned in the model whereby fourth thoracic vertebra (T4) and third lumbar vertebra (L3) were marked for pedicle screws placement (b), rod was put on concave side and with the help of different reduction manuals, coronal and sagittal balance of the spine was achieved. The rod was then applied on convex side to gain maximum correction (c)|
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Temporo-mandibular joint model
[Figure 3] shows the model of TMJ of the patient who presented with reduced mouth opening. The 3D reconstructed model of the patient revealed fusion between the temporal bone of the skull and neck of the mandible with the absorption of the head of the condylar process. Then, the model was used to plan surgery whereby 1 cm of block was excised at the junction of fusion. On the day of surgery, gap arthroplasty was done and 1 cm of the bone block was excised and 3.5 cm of mouth opening was achieved.
|Figure 3: Axial computed tomography image of bilateral temporo-mandibular joint (TMJ) ankylosis (a), three dimensional-reconstructed Skull model showing right sided TMJ ankylosis (blue arrow) with upward displaced coronoid process. Gap arthroplasty (brown line) and excision of coronoid process (red arrow) was practiced by burns and plastic surgeon team to achieve 2.5 cm of mouth opening before final surgery (b), final surgery (c)|
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Cleft alveolus model
[Figure 4] shows the model of the patient who was operated for cleft lip and palate an early age. The patient presented with the chief complaint of nasal regurgitation of liquids. The 3D-reconstructed model showed the gap in the alveolus with the oronasal fistula which aided the surgeons to interpret the patient's anatomy. It helped the surgeons to fill the gap and maintain the continuity of the maxilla with alveolar bone grafting.
|Figure 4: Axial computed tomography image of cleft alveolus indicated by yellow arrow (a), three dimensional reconstructed model of skull showing cleft of maxillary alveolus with a small nasal vestibular fistula (b), intraoperative image showing cleft in situ for which alveolar bone grafting from iliac crest was done (c)|
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Spleno-renal shunt model
[Figure 5] shows a 3D-reconstructed model of shunt surgery of a patient who was diagnosed with portal cavernoma by Doppler ultrasound. On follow-up period, CT-Angiography was done to assess the patency of the shunt. 3D reconstructed model allowed clearer observations of the relationship between the splenic and renal vein and patency of shunt was better delineated. The model was used for didactic purposes, training of resident doctors and to discuss with the patient.
|Figure 5: Postoperative axial computed tomography image of splenorenal shunt surgery (a), three dimensional (3D) reconstructed image of shunt surgery (b), 3D model of Splenorenal shunt (c). SV: Splenic vein, LRV: Left renal vein, SRS: Splenorenal shunt|
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Forty subjects completed the survey. In terms of level of experience, 40% were at consultant level (n = 16), whereas 60% (n = 24) were resident doctors. Of the respondents, 80% were <40 years of age, with the majority (85%) being of the male gender. Twenty-nine (96.66%) surgeons gave favorable responses when asked about the utility of these models in the visualization of pathological anatomy and preoperative planning. About 80% of the surgeons found it to be very helpful and 16% of surgeons found this technology to be helpful [Figure 6]. Most of the resident doctors (96%) agreed that 3D models would be helpful in learning surgery.
| Discussion|| |
Three-dimensional models have the number of applications in different specialties of medicine., We found this technique useful in creating the patient-specific 3D view of an organ for observation of unapparent anatomical details. It also helps surgeons and residents to practice their planned surgical procedures and sharpen their surgical skills. In this study, as the rehearsal of surgery was done before the final operation, the duration of surgery was reduced (129.090 ± 36.79 min; P < 0.05), blood loss minimized (130 ± 69.019 ml; P < 0.05) with fewer postoperative complications 6.25% (fever, delayed wound healing).
In the present study, 3D model of the spine provided the surgeon a real-time picture of the spine which was otherwise expected intra-operatively. 3D model helped in preventing any inadvertent injury to the cord due to clear visualization of pathological anatomy of the vertebra. It also helped in identifying the correct entry point for insertion of pedicle screw which was practiced before surgery. The surgical time, total number of blood transfusion, and complications (fever and delayed wound healing) were minimized as the surgeons had practiced the surgery in the model. The model also helped to explain the disorder and the associated risk of surgery to the patient and their relative. Good correlation between preoperative planning and the postoperative result was found when 3D printed pelvic models were used for surgical reconstruction of the fractured pelvis. The 3D-printed models can provide many advantages to head and neck, maxillofacial and plastic surgeons in creating pre-operative complex constructs with high precision. Reconstruction and rehabilitation surgery in patients with a history of trauma, fracture and tumors in the facial region can be benefitted by 3D printed models as it offers reproducible, precise, and patient-specific models for surgery. It also improves postoperative facial contour symmetry and thus enhances the psychological status of the patient suffering from significant scarring, deformation, and asymmetry.
3D-printed model is ideal for surgical preparation because of variations in the human body. Jones et al. mentioned anatomical models produced by 3D technology for planning surgery, training of residents, and teaching medical undergraduates were extremely helpful to the operative team both preoperatively and intraoperatively. 3D model encourages fabrication of specimen so it can replicate a rare specimen, thus anatomical models can be made available for a specific lecture class for teaching medical students. Availability of tactile model of patient's anatomy is advantageous in comparison to rely solely on magnetic resonance imaging or CT scans. Different specialties have explained the value of 3D-printed models in vascular and soft tissue mapping. These models helped clinicians to observe patient's anatomy preoperatively which reduced guesswork and decreased the duration of surgery. The clinical use of 3D printing is increasing in the field of surgical gastroenterology. In this study 3D model of the proximal spleno-renal shunt was used for teaching and training purposes and without any intent to use clinically.
Sometimes, it is tough to teach surgical skills to the residents for the first time in the operation theatre. 3D technology can be combined into resident training to practice their skill through the use of high fidelity models. The study by Fasel et al. reveal CT based 3D reconstruction exhibits good correlation with the anatomy in both qualitative and quantitative aspect. As variations and diseased conditions can be well appreciated, early exposure of medical Residents to 3D printed models will build up interest in surgical branches. Based on the answers received from the surgeons using the 3D models, we found that most surgeons were satisfied. This technique enabled all of them to choose appropriate treatment planning and surgical steps. The operative time was reduced considerably (129.090 ± 36.79 min; P < 0.05) and only 6.25% complication was observed. The present study closely resembles the study done by Jones et al. up to some extent and based on the results we totally agree with the authors.
This study is based on clinical cases from different surgical specialties. This research contains data from various surgical departments across a single medical institution thus adding a comprehensive nature to the analysis undertaken, whereas other studies have done research pertinent to a particular surgical discipline.,, Randomization is the major limitation of the current study. There is the requirement of randomized clinical trials to prove the superiority of 3D planning over classical surgical approaches. Other limitations are the time associated with producing patient-specific model. This technology takes 1–2 days to create a 3D model thus limiting its usefulness in emergency surgeries. Despite limitations mentioned, three-dimensional modeling may improve surgical education and clinical practice.
| Conclusion|| |
3D models are useful for clinicians to observe patients' anatomy preoperatively. Presurgical planning in 3D printed model reduces guesswork and thus it remarkably reduces surgical time, blood loss, minimizes complication, and thereby improves surgical outcome. These models are helpful to teach surgical skills to the residents before going to the operation theater. It also helps in explaining to patients and relatives about surgery and taking informed consent.
- We are thankful to faculty of Anatomy Department for their support in preparing the manuscript
- The authors acknowledges the assistance provided by 3D Lab application engineer Mr. Ravi Kant and 3D Artist Md. Shamshad Ansari.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]