3D printing assisted MIPO for treatment of complex middle-proximal humeral shaft fractures.

BACKGROUND: This study was designed to explore the clinical efficacy of 3-dimensional (3D) printing assisted minimally invasive percutaneous plate osteosynthesis (MIPO) technique by comparing the clinical outcomes with traditional open reduction and internal plating fixation (ORIF) for treating complex middle-proximal humerus fractures (AO 12C fracture type). MATERIALS AND METHODS: The data of 42 participants who received a complicated middle-proximal humerus fracture from the beginning of 2018 to the end of 2022 were retrospectively analyzed. All patients were assigned to two groups: MIPO with detailed preoperative planning assisted by 3D printing technique (MIPO group), and traditional ORIF (ORIF group). RESULTS: This study included 21 patients in the ORIF group and 21 patients in the MIPO group. All patients were followed-up for at least one year (mean: 16.12 ± 4.13 months), and no difference was observed in the range of shoulder joint motion (ROM), Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores and Constant scores between the two groups. However, the occurrence of complications (surgical incision site infection, implant loosening, bone nonunion and radial nerve palsy) in ORIF group was remarkably higher compared to the MIPO group. All the cases achieved bone union within the MIPO group. Significant differences were found in surgical time, intraoperative blood loss and fracture healing time between the two groups. CONCLUSION: Preoperative 3D printing assisted MIPO technique exhibits obvious advantages in high operational efficiency and low occurrence of complications, which is worthy of clinical application for treating complex middle-proximal humeral shaft fractures.

Investigation of the effectiveness of preoperative intubation simulation using a custom-made simulator for pediatric patients with difficult airway: a pilot study.

The purpose of this study is to investigate whether preoperative intubation simulation using custom-made simulator is useful during anesthesia induction for the children who have difficult airway. We included the children under 15 years of age who have difficult airway which had been already known. Prior to the scheduled surgery, CT imaging was performed and a 3D reconstruction of the face from the chest was performed. Then custom-made airway simulator was made. We tried to intubate custom-made simulator of patients preoperatively. We planned how to intubate the patient for anesthesia induction from the result of intubation simulation. The findings of direct laryngoscopy were compared with the findings during intubation. Three patients were included in this study. It took up to 3 weeks to create a simulator, which was difficult due to time constraints to accommodate emergency surgeries. Simulation findings correlated well with findings during anesthesia induction. There were no cases of severe hypotension or hypoxia during induction of anesthesia with the planned intubation method. In conclusion, preoperative intubation simulation using custom-made simulator may be useful for the patients who have difficult airway.

Simulation of the occipital transtentorial approach incorporating visualization of the cerebellar tentorium using three-dimensional computed tomography angiography and gadolinium-enhanced T1-weighted magnetic resonance imaging: technical note.

The occipital transtentorial approach (OTA) is one of the useful approaches to the lesions of the pineal region, dorsal brainstem, and supracerebellar region. However, a wide operative field is sometimes difficult to obtain due to the tentorial sinus and bridging veins. This study evaluated the usefulness of preoperative simulation of OTA, specifically including the cerebellar tentorium in 9 patients. All patients underwent computed tomography angiography and venography and gadolinium-enhanced three-dimensional T1-weighted magnetic resonance images (Gd-3D-T1WI). The images were fused, and the cerebellar tentorium, vessels, and tumor were manually extracted from Gd-3D-T1WI to obtain the simulation images. Visualization of the cerebellar tentorium could discriminate between bridging veins from the occipital lobe and cerebellum, and recognize the site of bridging to the tentorial sinus and variants which may interfere with the tentorial incision. Simulation of the tentorial incision was also possible based on the relationships between the tumor, tentorial sinus, bridging vein, and cerebellar tentorium. The simulation suggested that safe tentorial incision was difficult in two sides because of the crossed tentorial sinus draining the left basal vein and draining veins from the glioblastoma. The OTA was performed in eight cases, and no difficulty was experienced in the tentorial incision in all cases. The simulation findings of the bridging vein and tentorial sinus were consistent with the intraoperative findings. Preoperative simulation including the cerebellar tentorium is useful for determining the optimum and safe side and required extent of the tentorial incision necessary for tumor resection with the OTA.

Influence of preoperative simulation on the reduction quality and clinical outcomes of open reduction and internal fixation for complex proximal humerus fractures.

PURPOSE: Proximal humerus fractures (PHFs) are common. With the development of locking plates, open reduction and internal fixation (ORIF) of the proximal humerus can provide excellent clinical outcomes. The quality of fracture reduction is crucial in the locking plate fixation of proximal humeral fractures. The purpose of this study was to determine the impact of 3-dimensional (3D) printing technology and computer virtual technology assisted preoperative simulation on the reduction quality and clinical outcomes of 3-part and 4-part proximal humeral fractures. METHOD: A retrospective comparative analysis of 3-part and 4-part PHFs undergoing open reduction internal fixation was performed. Patients were divided into 2 groups according to whether computer virtual technology and 3D printed technology were used for preoperative simulation: the simulation group and the conventional group. Operative time, intraoperative bleeding, hospital stay, quality of fracture reduction, Constant scores, American Society for Shoulder and Elbow Surgery (ASES) scores, shoulder range of motion, complications, and revision surgeries were assessed. RESULTS: This study included 67 patients (58.3%) in the conventional group and 48 patients (41.7%) in the simulation group. The patient demographics and fracture characteristics were comparable in these groups. Compared with the conventional group, the simulation group had shorter operation time and less intraoperative bleeding (P < 0.001, both). Immediate postoperative assessment of fracture reduction showed a higher incidence of greater tuberosity cranialization of < 5 mm, neck-shaft angle of 120° to 150°, and head shaft displacement of < 5 mm in the simulation group. The incidence of good reduction was 2.6 times higher in the simulation group than in the conventional group (95% CI, 1.2-5.8). At the final follow-up, the chance of forward flexion > 120° (OR 5.8, 95% CI 1.8-18.0) and mean constant score of > 65 (OR 3.4, 95% CI 1.5-7.4) was higher in the simulation group than the conventional group, as well as a lower incidence of complications in the simulation group was obtained (OR 0.2, 95% CI 0.1-0.6). CONCLUSIONS: This study identified that preoperative simulation assisted by computer virtual technology and 3D printed technology can improve reduction quality and clinical outcomes in treatment of 3-part and 4-part PHFs.

Evaluation of relationship between splenic artery and pancreatic parenchyma using three-dimensional computed tomography for laparoscopic distal pancreatectomy.

AIM: Isolating the root of the splenic artery (SPA) is a challenging procedure in laparoscopic distal pancreatectomy (LDP). We investigated the usefulness of evaluation of the relationship between the SPA and pancreatic parenchyma using three-dimensional computed tomography (3D-CT). METHODS: In total, 104 patients were evaluated. The relationship between the SPA and pancreatic parenchyma was classified into two types: buried and non-buried. Video clips of 50 patients who underwent LDP requiring isolation of the SPA root were reviewed to determine whether the classification is related to difficulty of LDP. RESULTS: Of the 50 assessed patients who underwent LDP, the relationship between the SPA and pancreatic parenchyma was the buried type in 30 (60.0%) and non-buried type in 20 (40.0%). The buried type was associated with a significantly longer median operative time than the non-buried type (285.0 vs. 235.5 min, respectively; P < 0.01). The median time required to isolate the SPA in the buried type (25.8 min; range, 4.0-101 min) was significantly longer than that in the non-buried type (7.0 min; range, 1.0-27.0 min) (P < 0.001). CONCLUSION: Preoperative 3D-CT around the pancreas is practical for predicting the difficulty of SPA isolation and determining the safety of the procedure.

Utility of a three-dimensional printed pelvic model for lateral pelvic lymph node dissection.

PURPOSE: In patients with advanced lower rectal cancer, the complex pelvic anatomy renders lateral pelvic lymph node dissection to be challenging. Therefore, we evaluated the utility of printing a three-dimensional (3D) pelvic model for lateral pelvic lymph node dissection. METHODS: We included 22 patients who underwent lateral pelvic lymph node dissection for rectal cancer between June 2017 and February 2019. Using CT scans, 3D pelvic images and models were constructed and printed, respectively. Thirty colorectal surgeons subjectively evaluated the utility of 3D pelvic models based on a 5-point Likert scale questionnaire (1 = strongly disagree, 5 = strongly agree). RESULTS: The average Likert score for the question "Would a 3D model be useful for understanding pelvic anatomy?" was 4.68. Cases with clinically diagnosed metastatic lymph nodes (4.79 ± 0.44) scored higher than those without them (4.38 ± 0.77, p = 0.02). For spatial comprehension of pelvic anatomy, 3D models scored higher (4.83) than 3D images (4.36, p < 0.001). The ease of use of 3D models and images was scored 4.60 and 4.20, respectively (p = 0.015). With experience, the 3D image reconstruction time decreased from 900 to 150 min. CONCLUSION: The 3D pelvic models may be helpful for experienced surgeons to understand the pelvic anatomy in lateral pelvic lymph node dissection.

Virtual reality with three-dimensional image guidance of individual patients' vessel anatomy in laparoscopic distal pancreatectomy.

PURPOSE: Three-dimensional virtual endoscopy (3DVE) has the potential advantage of enhanced anatomic delineation and spatial orientation during laparoscopic procedures. In the present study, we aimed to evaluate the impact of 3DVE guidance in laparoscopic distal pancreatectomy (LDP). METHODS: Thirty-eight patients presenting to our hospital with a variety of pancreatic tumors underwent preoperative computed tomography scanning to clearly define the major peripancreatic vasculature and correlate it with a 3DVE system (SYNAPSE VINCENT: Fujifilm Medical, Tokyo, Japan). This map served as the guide during preoperative planning, surgical education, and simulation and as intraoperative navigation reference for LDP. Operative records and pathological findings were analyzed for each procedure. Operative parameters were compared between the 38 patients in this study and 8 patients performed without 3DVE guidance at our institution. RESULTS: The 3DVE navigation system successfully created a preoperative resection map in all patients. Relevant peripancreatic vasculature displayed on the system was identified and compared during the intervention. The mean blood loss in LDP performed under 3DVE guidance versus LDP without 3DVE was 168.5 +/- 347.6 g versus 330.0 +/- 211.4 g, p = 0.008 while and the operative time was 171.9 +/- 51.7 min versus 240.6 +/- 24.8 min, p = 0.001. CONCLUSIONS: 3DVE in conjunction with a "laparoscopic eye" creates a preoperative and intraoperative three-dimensional data platform that potentially enhances the accuracy and safety of LDP.

Preoperative simulation for complex transposition of great arteries using a three-dimensional model.

We utilised a cast preoperatively prepared on the basis of the patient's computed tomography data to clarify unusual orientation of the great arteries (transposition of great arteries, coarctation of the aorta, and abnormally branching central pulmonary arteries) in a 2.2-kg neonate. The three-dimensional model was very useful for designing the surgical procedure - being easy to handle for real and precise simulation of the reparative manoeuvres.

Efficacy of non-rigid registration technique for misregistration in 3D-CTA fusion imaging.

PURPOSE: To assess whether fusion 3D-CTA images can be corrected using non-rigid registration (NRR) for gastroenterology imaging. METHODS: This study included 55 patients before gastroenterology surgery who underwent preoperative 3D-CTA prior to gastroenterological surgery. We recorded the coordinate of measurement points on the arterial vessels (X, Y, and Z) in each portal phase, original image of the arterial phase, and arterial phase with NRR. The distance of misregistration between the two points was calculated with the coordinate of the original image with NRR and that of the portal phase as true value. RESULTS: The distance of misregistration between the two points in the original arterial and portal phase images was significantly higher than that in the arterial phase image with NRR on all directions (p < 0.01). CONCLUSIONS: This study showed that NRR may correct misregistration on fusion 3D-CTA imaging. Hence, it can visualize correctly the anatomy of the vessel.

Contralateral Approach Based on a Preoperative 3-Dimensional Virtual Osteotomy Technique for Anterior Circulation Aneurysms.

OBJECTIVE: Our objective was to review 15 consecutive patients with anterior circulation aneurysms managed through a contralateral approach. Individualized surgical simulation using three-dimensional (3D) imaging was adopted to enable safe performance of clipping surgery. METHODS: Five patients had multiple intracranial aneurysms, and 10 patients had a single aneurysm on the contralateral side of the craniotomy. Preoperatively, the unique architecture of aneurysms was fully understood in their 3-dimensionality reconstructed by Mimics software. The location of the cranial bone window and the patient's head position was individually optimized using a preoperative simulation system. RESULTS: In this cohort, 17 contralateral aneurysms showed no wall calcifications. Projections of the aneurysms were superomedial (3/17, 17.6%), medial (8/17, 47.1%), posterior (3/17, 17.6%), and superior (3/17, 17.6%). The visual similarity between the simulating scene and the operative view was excellent in 100% of the cases. Four patients were treated with a contralateral pterional approach, and the remaining 11 patients were treated with a contralateral supraorbital keyhole approach. All of them were well-clipped, except 1 blister-like aneurysm being wrapped. All 15 patients had good outcomes (mRS ≤ 3) after a mean 13 months follow-up. There were no recurrences after surgical treatment. CONCLUSIONS: The contralateral approach for the selected anterior circulation aneurysms is feasible in experienced hands with acceptable morbidity. This approach should be the choice only under judicious case-to-case planning based on a preoperative 3D virtual osteotomy technique.

Device-specific evaluation of intraventricular left ventricular assist device position by quantitative coaxiality analysis.

BACKGROUND: Patient-specific anatomy may influence the final intraventricular positioning of inflow cannula in left ventricular assist device (LVAD) recipients. An association exists between such positioning and clinical outcomes (specifically, orientation toward the interventricular septum has negative prognostic implications). Alternative commercially available LVADs are characterized by markedly different design, with potential consequences on intrathoracic fitting among individual patients. MATERIAL AND METHODS: A cohort of 13 LVAD recipients (either HeartMate II-group A or Jarvik 2000 Flowmaker-group B) was evaluated. On postoperative computed tomography scans, we reconstructed the implanted LVAD (semiautomatic segmentation), defined the target mitral orifice (3D Slicer software), and built a coordinate system to quantify the coaxiality of the cannula with the mitral valve axis (angles φ and θ, expressed as percentage variation from the ideal value φ = Î¸ = 0°). RESULTS: Group A presented significantly greater average percentage variation of the φ angle (significantly greater orientation of the intraventricular cannula toward the interventricular septum; 33.2% ± 32.1% versus 1.9% ± 0.9%, P = 0.001). Group A presented significantly greater average percentage variation of the θ angle (52.7% ± 23.6% versus 14.5% ± 6.3%, P = 0.013). CONCLUSIONS: The device assessed in group B showed in the present series better average coaxiality with the mitral orifice. Such finding is related with its design (total intraventricular placement) and interaction with thoracic structures. The present method is being integrated in the development of LVAD virtual implantation tools and may help physicians in patient-specific selection among alternative devices.

A systematic examination of preoperative surgery warm-up routines.

BACKGROUND: Recent evidence indicates that a preoperative warm-up is a potentially useful tool in facilitating performance. But what factors drive such improvements and how should a warm-up be implemented? METHODS: In order to address these issues, we adopted a two-pronged approach: (1) we conducted a systematic review of the literature to identify existing studies utilising preoperative simulation techniques; (2) we performed task analysis to identify the constituent parts of effective warm-ups. We identified five randomised control trials, four randomised cross-over trials and four case series. The majority of these studies reviewed surgical performance following preoperative simulation relative to performance without simulation. RESULTS: Four studies reported outcome measures in real patients and the remainder reported simulated outcome measures. All but one of the studies found that preoperative simulation improves operative outcomes-but this improvement was not found across all measured parameters. While the reviewed studies had a number of methodological issues, the global data indicate that preoperative simulation has substantial potential to improve surgical performance. Analysis of the task characteristics of successful interventions indicated that the majority of these studies employed warm-ups that focused on the visual motor elements of surgery. However, there was no theoretical or empirical basis to inform the design of the intervention in any of these studies. CONCLUSIONS: There is an urgent need for a more rigorous approach to the development of "warm-up" routines if the potential value of preoperative simulation is to be understood and realised. We propose that such interventions need to be grounded in theory and empirical evidence on human motor performance.

Preoperative simulation of the running course of the abducens nerve in a large petroclival meningioma: a case report and literature review.

One of the most important and useful pieces of information in the preoperative evaluation of a large petroclival meningioma is the running course of the abducens nerve. The abducens nerve is small and has a long intracranial course, making it prone to compression by the tumor at various anatomical points. In relatively large tumors, it is difficult to confirm the entire course of the abducens nerve, even by heavy T2-thin slice imaging. We report a case of successful preoperative estimation of the course of the abducens nerve that aided in its complete preservation during the resection of a large petroclival tumor.

Virtual implantation of a novel LVAD: toward computer-assisted surgery for heart failure.

BACKGROUND: Mechanical and hemodynamic factors are among the determinants of patient-device interaction and early-term and long-term outcomes in left ventricular assist device (LVAD) recipients. MATERIAL AND METHODS: We are currently developing computer simulation tools aimed at (1) analyze the intrathoracic and intracavitary positioning of LVADs after implantation and establish correlation with clinical outcomes; (2) assist surgeons in the choice of device and of left ventricular coring site for optimized intrathoracic placement and function; and (3) facilitate the planning of less-invasive LVAD implantation. A virtual representation of LVAD (mesh device component) was created through cone-beam computed tomography and semiautomatic segmentation. A modular framework software (CamiTK, Grenoble, France) was used to create a three-dimensional representation of patients' computed tomography (CT) scan and incorporate the mesh device component for virtual implantation. RESULTS: Device reconstruction was included into a dedicated software with the purposes of virtual implantation, based on the preoperative CT scan of surgical candidates. CONCLUSIONS: We present herein the first digital reconstruction of the novel HeartMate 3 LVAD. Virtual implantation on the basis of preoperative CT scan is feasible within a user-friendly interactive software. Future studies will be focused on correlation with clinical variables.

[SENDS criteria from the diversification of MAST procedures. Implementation of preoperative simulation]. / SENDS-Kriterien als Entwicklungstheorem der MAST­Prozeduren. Einführung präoperativer Simulation.

CLINICAL ISSUE: Minimal access spinal technologies (MAST) lead to a diversification of surgical procedures, which requires careful selection of the procedure and outcome monitoring. For a rational selection of the procedure simulation, endoscopy, navigation, decompression and stabilization (SENDS) criteria can be derived from the development of the MAST procedures. Preoperative simulation has diagnostic and therapeutic values. The SENDS criteria can be verified indirectly via outcome control. STANDARD TREATMENT: Biomechanically meaningful diagnostic x-rays of the spinal segment to be surgically treated are currently carried out with the patient in inclination and reclination. TREATMENT INNOVATIONS: Software-related preoperative simulation based on these x-ray images facilitates the selection and implementation of the MAST procedure. DIAGNOSTIC WORK-UP: For preoperative simulation motion shots are needed in inclination, neutral position and reclination and the dimensions can be obtained using an x-ray ball or a computed tomography (CT) scan. PERFORMANCE: The SENDS criteria are useful because established procedures based on these criteria reach a comparable outcome. Preoperative simulation appears to be a useful selection criterion. ACHIEVEMENTS: Preoperatively it is necessary to collate patient and segment information in order to provide each patient with individualized treatment. So far there is no evidence for a better outcome after preoperative simulation but a reduction of surgery time and intraoperative radiation exposure could already be demonstrated. PRACTICAL RECOMMENDATIONS: Minimally invasive methods should be preferred if there is a comparable outcome. The establishment of new procedures has to be accompanied by the maintenance of a spine register. Minimally invasive surgical procedures should be individualized for each patient and segment. Mobility X-ray images should be prepared for use with the preoperative simulation as the information content significantly increases with respect to the MAST procedure.

Does warming up improve surgical outcome in total hip arthroplasty?

PURPOSE: Warming up prior to surgery has been shown to enhance surgeons' performance during laparoscopic procedures. It is unknown whether or not warming up prior to total hip arthroplasty (THA) will have a similar effect on surgical outcome. METHODS: We retrospectively evaluated the effect of warming up on the intraoperative outcome of 82 patients who underwent a primary THA with identical implants. The patients were divided equally into two groups. Group 1 (first case of the day) served as "warm-up procedure," while Group 2 (second case of the day) was the "post-warm-up procedure." RESULTS: We found no statistically significant difference when we compared cup abduction and anteversion angles, femoral offset, postoperative LLD, stem alignment, hip center of rotation and femoral stem canal fill between the two groups (p > 0.05). CONCLUSION: Warming up prior to performing surgery does not make a difference for primary THA when performed by an experienced surgeon. However, these results may not reflect its effect on procedures that require fine motor skills or done by an orthopedic trainee or less experienced surgeons.

Three-dimensional Images Fusion Method Useful for Preoperative Simulation of Clipping Surgery for Cerebral Aneurysms.

This study aimed to introduce a three-dimensional (3D) images fusion method for preoperative simulation of aneurysm clipping. Consecutive unruptured aneurysm cases treated with surgical clipping from March 2021 to October 2023 were included. In all cases, preoperative images of plain computed tomography (CT), CT angiography, magnetic resonance imaging (MRI) 3D fluid-attenuated inversion recovery, 3D heavily T2-weighted images, and 3D rotational angiography were acquired and transported into a commercial software (Ziostation2 Plus, Ziosoft, Inc. Tokyo, Japan). The software provided 3D images of skull, arteries including aneurysms, veins, and brain tissue that were freely rotated, magnified, trimmed, and superimposed. Using the 3D images fusion method, two operators predicted clips to be used in the following surgery. The predicted clips and actually used ones were compared to give agreement scores for the following factors: (1) type of clips (simple or fenestrated), (2) shape of clips (straight, curved, angled, or bayonet), and (3) clipping strategy (single or multiple). The agreement score ranged from 0 to 3 because a score of 1 or 0 was given for agreement or disagreement on each factor. Interoperator reproducibility was also evaluated. During the study period, 44 aneurysms from 37 patients were clipped. All procedures were successfully completed, thanks to the precisely reproduced surgical corridors with the 3D images fusion method. Agreement in clip prediction was good with mean agreement score of 2.4. Interobserver reproducibility was also high with the kappa value of 0.79. The 3D images fusion method was useful for preoperative simulation of aneurysm clipping.

To further incorporate computer-aided designs to improve preoperative planning in total hip arthroplasty: a cohort study.

Background: Hip replacement surgeries are increasing in demand, requiring rigorous improvements to a mature surgical protocol. Postoperative patient dissatisfaction mainly stems from postoperative complications resulting from the inappropriate selection of prostheses to meet the needs of each patient. This results in prosthesis loosening, hospital-related fractures, and postoperative complex pain, which can all be attributed to inappropriate sizing. In this study, we aimed to further explore the intraoperative and postoperative benefits of incorporating computer-aided design (CAD) in preoperative planning for total hip arthroplasty (THA). Methods: A total of 62 patients requiring total hip replacement surgery from January 2021 to December 2021 were collected and randomly divided into a preoperative computer-aided simulated group and a conventional x-ray interpretation group. The accuracy of implant size selection (femoral and acetabular implant) between the preoperative planning and surgical procedure of the two groups was compared. Patient parameters, perioperative Harris hip scores, operative time (skin-to-skin time), surgical blood loss, and postoperative hospital stay were recorded, and the differences between the two groups were statistically compared using a single sample t-test. Results: All patients in the study were successfully operated on and achieved good postoperative functional recovery. With CAD, the selection of the most suitable-sized prosthesis was significantly more accurate compared to the control group (accuracy of the acetabular component between the CAD/control: 80.6%/61.3%, and accuracy of the femoral component: 83.9%/67.7%). Intraoperative blood loss (177.4/231.0 ml, P = 0.002), operation time (84.2 ± 19.8 min/100.3 ± 25.9 min, P = 0.008), duration of hospital stay (6.5 ± 3/9.1 ± 3.9 days, P = 0.003), and postoperative Harris hip score (81.9 ± 6.5/74.7 ± 11.1, P = 0.003) were compared to the control group and showed statistical significance. Conclusion: Incorporating CAD into the preoperative planning of total hip arthroplasty can effectively guide the selection of the most suitable-sized prosthesis, reduce intraoperative blood loss, and promote short-term functional recovery after THA.

Preoperative Simulation of Intraoperative Findings in Surgical Clipping of Posterior Communicating Artery Aneurysms Using T2-Weighted 3D Images.

BACKGROUND: Tentorium resection and detachment from the oculomotor nerve are sometimes required for surgical clipping of unruptured posterior communicating artery (PCoA) aneurysms. Using T2-weighted 3D images, we aimed to identify the preoperative radiological features required to determine the necessity of these additional procedures. METHODS: We reviewed 30 patients with unruptured PCoA aneurysms who underwent surgical clipping and preoperative simulation using T2-weighted 3D images for measurement of the distance between the tentorium and aneurysm. Aneurysms were classified into superior type (superior to the tentorium) and inferior type (inferior to the tentorium). RESULTS: Seven patients (23%) underwent tentorium resection; all had the inferior type (superior vs. inferior, 0% vs. 33%, p = 0.071). In the 21 patients with the inferior type, the distance from the tentorium to the aneurysmal neck was 2.2 ± 1.1 mm and 0.0 ± 0.5 mm without and with tentorium resection (p < 0.01), respectively. An optimal cutoff value of ≤ +0.84 mm was identified for tentorium resection (area under the curve (AUC) = 0.96). Furthermore, 17 patients (57%) showed tight aneurysm attachment to the oculomotor nerve; all had the inferior type (0% vs. 81%, p < 0.01). The distance from the aneurysm tip to the tentorium was 1.1 ± 1.2 mm and -1.7 ± 1.4 mm without and with attachment (p < 0.01). The optimal cutoff value was ≤ +0.45 mm (AUC = 0.92). CONCLUSIONS: Measurement of the distance between the tentorium and aneurysmal neck or tip with T2-weighted 3D images is effective for preoperative simulation for surgical clipping of PCoA aneurysms.

Useful Preoperative Simulation of Laparoscopic Surgery for Rectal Cancer in Patients with Kyphosis.

Kyphosis complicates abdominal surgery. Here, we report a case of rectal cancer in a patient with kyphosis who underwent successful laparoscopic surgery after a preoperative simulation. An 81-year-old woman with rectal cancer was admitted to our department, and laparoscopic surgery was planned. Physical examination revealed severe kyphosis. To ensure successful laparoscopic surgery, we conducted a detailed preoperative simulation, including three-dimensional CT simulations of port arrangement and anatomy, simulation of body position, selection of surgical instruments, and preoperative discussion with the anesthesiologist. We planned to insert the first port in the umbilical region for pneumoperitoneum and the camera port in the ventral region under pneumoperitoneum. We planned to insert the ports on the right side of the patient's body from the caudal regions, after considering the location of the inferior mesenteric artery and the limitations in degrees and space attributable to the costal arch and promontorium. Beach chair position was planned. We used a fan-shaped retractor and sponge retractor to remove the small intestine from the surgical view. In preoperative discussions with the anesthesiologist, we decided to maintain pneumoperitoneum pressure at less than 8 mm Hg during the operation, to safeguard respiratory function. Lower anterior resection with D2 lymph node dissection was performed, without intraoperative complications. At 2 years postoperatively, the patient was healthy with no signs of recurrence. Laparoscopic surgery appears to be a suitable choice for patients with kyphosis. We believe that preoperative simulation will result in successful outcomes.