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While the insertion of the arthroscope into the elbow joint is relatively easy based on anatomical landmarks, obtaining a correctly located instrument portal is often difficult. Therefore, the goal of the study was to create a 3D-printed prototype of an aiming device for the guiding needle, and to check its feasibility. The study included fresh cadavers of 15 dogs, 9 males and 6 females, aged from 1 to 6 years (median 4 years) with body weight from 17 to 57 kg (median 30 kg). On each dog, we compared the number of attempts needed to obtain optimal direction of the guiding needle for the portal, using one elbow the prototype, and performing this as control on the opposite joint without the prototype (with a free hand). The number of attempts needed was significantly lower using the prototype (median 1) than on the control elbows (median 2, p = 0.009). The number of attempts was not correlated with the body weight neither in the case of experimental (Rs = 0.18, p = 0.532) nor control elbows (Rs = 0.13, p = 0.642). We conclude that the used prototype seems to be helpful in elbow joint arthroscopy.

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RATIONALE AND OBJECTIVES: To evaluate the targeting accuracy of laser-guided punctures in combination with an aiming device for computed tomography (CT) interventions during in vitro experiments. MATERIALS AND METHODS: A total of 600 CT-guided punctures were performed using a laser target system, half of them with the additional help of an aiming device. Conically shaped targets in a plexiglass phantom were punctured. The planning CT data sets were acquired with 1.25, 2.5 and 5 mm slice thickness. Needle placement accuracy, as well as procedural time, was assessed. The Euclidean (ED) and normal distances (ND) were calculated at the target point. RESULTS: Using the aiming device, the accomplished mean ND at the target for the 1.25, 2.5 and 5 mm slice thickness was 1.76 mm (SD ± 0.92), 2.09 mm (SD ± 1.06) and 1.93 mm (SD ± 1.38), respectively. Without aiming device, the corresponding results were 2.55 mm (SD ± 1.42), 2.7 mm (SD ± 1.43) and 2.31 mm (SD ± 1.64). At a slice thickness of 1.25 mm and 2.5 mm, punctures with the aiming device were significantly more accurate for both the ED and ND as compared to the punctures without aiming device (p < 0.001). The mean time required to complete the procedure, including image acquisition, trajectory planning, the placement of 10 needles, and the control-CT scan was 24.8 min without and 29.8 min with the aiming device. CONCLUSION: The additional use of the aiming device in combination with the commercially available laser guidance system significantly increased the level of accuracy during this in vitro experiment compared to freehand passes.

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PURPOSE: The outlet of the classic sacroiliac screw (SIS) cannot be precisely controlled by aiming devices, which may lead to malpositioned implants and neurovascular and visceral injury. This study aimed to radio-anatomically measure the parameters of the channel for anterior-posterior placement SIS (AP-SIS), which can be placed percutaneously with an aiming device. METHODS: Pelvic CT scan data of 80 healthy adults (40 males and 40 females) with an average age of 45 years (range 20-70 years) were collected. The length (L), width (W), height (H), cortical bone spacing (M), camber angle (E), anteversion angle (F), cross-sectional safety angle (P) and sagittal safety angle (Q) of the channel were measured by CT or Mimics software. RESULTS: The L, W, H, M, E, F, P and Q measures of S1 were 109.2 ± 8.0 mm, 18.5 ± 1.9 mm, 21.7 ± 1.7 mm, 8.1 ± 0.4 mm, 44.2 ± 3.2°, 42.4 ± 3.6°, 16.8 ± 1.1°, and 19.4 ± 2.0°, respectively, for S1, and 113.5 ± 9.4 mm, 18.2 ± 1.5 mm, 21.7 ± 1.7 mm, 7.7 ± 0.4 mm, 44.7 ± 3.2°, 31.2 ± 2.7°, 13.8 ± 1.0° and 15.4 ± 1.4°, respectively, for S2. Of the L measures, the intra-iliac segment was slightly longer than the intra-sacral segment. All parameters showed significant sex-related differences (p < 0.05). CONCLUSION: The AP-SIS channels of S1-2 have sufficient width and length to accommodate a cancellous screw with a Φ 7.0-8.0 mm and a length 90-130 mm. The intra-iliac segment is a long channel screw with better mechanical properties over classic SIS.

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A standardized periapical radiograph is still the most suitable technique for monitoring peri-implant osseous destruction during long-term treatment. This article describes a new method for custom fabrication of an acrylic template with standardized reproducible assessment of implants retaining mandibular bar overdentures, without removal of the bar and regardless of the implant system used.

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OBJECTIVE Complications of laser interstitial thermal therapy (LITT) are underreported. The authors discuss how they have modified their technique in the context of technical and treatment-related adverse events. METHODS The Medtronic Visualase system was used in 49 procedures in 46 patients. Between 1 and 3 cooling catheters/laser fiber assemblies were placed, for a total of 62 implanted devices. Devices were placed using frameless stereotaxy (n = 3), frameless stereotaxy with intraoperative MRI (iMRI) (n = 9), iMRI under direct vision (n = 2), MRI alone (n = 1), or frame-based (n = 47) techniques. LITT was performed while monitoring MRI thermometry. Indications included brain tumors (n = 12), radiation necrosis (n = 2), filum terminale ependymoma (n = 1), mesial temporal lobe epilepsy (n = 21), corpus callosotomy for bifrontal epilepsy (n = 3), cavernoma (n = 1), and hypothalamic hamartomas (n = 6). RESULTS Some form of adverse event occurred in 11 (22.4%) of 49 procedures. These included 4 catheter malpositions, 3 intracranial hemorrhages, 3 cases of neurological deficit related to thermal injury, and 1 technical malfunction resulting in an aborted procedure. Of these, direct thermal injury was the only cause of prolonged neurological morbidity and occurred in 3 of 49 procedures. Use of frameless stereotaxy and increased numbers of devices were associated with significantly increased complication rates (p < 0.05). A number of procedural modifications were made to avoid complications, including the use of 1) frame-based catheter placement, a 1.8-mm alignment rod to create a track and titanium skull anchors for long trajectories to improve accuracy; 2) a narrow-gauge instrument for dural puncture and coregistration of contrast MRI with CT angiography to reduce intracranial hemorrhage; 3) general endotracheal anesthesia for posterior-placed skull anchors to reduce the likelihood of damage to the cooling catheter; 4) use of as few probes as possible to reduce complications overall; and 5) dose modification of thermal treatment and use of short (3-mm) diffusing tips to limit treatment when structures to be spared do not have intervening CSF spaces to act as heat sinks. CONCLUSIONS Laser ablation treatment may be used for a variety of neurosurgical procedures for patients with tumors and epilepsy. While catheter placement and thermal treatment may be associated with a range of suboptimal operative and postoperative courses, permanent neurological morbidity is less common. The authors' institutional experience illustrates a number of measures that may be taken to improve outcomes using this important new tool in the neurosurgical arsenal.

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Objective To evaluate the clinical efficacy of a self-designed novel n-shaped aiming device in aiding the percutaneous cannulated screwing for treatment of odontoid fractures of Anderson-D' Alonzo type Ⅱ and shallow type Ⅲ.Methods A retrospective analysis was conducted of the 17 patients who had been treated at our department for odontoid fracture of Anderson-D' Alonzo type Ⅱ and shallow type Ⅲ between January 2009 and December 2013.They were 13 males and 4 females,with an average age of 37.5 years (from 16 to 61 years).All received surgical treatment after skull traction or jaw pillow traction preoperatively for reduction.Intraoperatively,percutaneous cannulated screwing via the anterior cervical approach was performed with the help of a self-designed novel n-shaped aiming device to fix the odontoid.Postoperatively,X-ray and CT scan were used to check the screw locations and evaluate the fracture healing.Results The 17 cases were followed up for 6 to 15 months (average,10.5 months).No intraoperative injury to the esophagus,artery,spinal cord or nerve root happened.The operating time ranged from 60 to 125 min.The bleeding was from 10 to 40 mL.Intraoperative observation revealed fine locations of the screws.Bony union was achieved in 16 cases 3 months postoperatively while separation and hardening of the fracture ends was found in one ease.Conclusion Our self-designed novel n-shaped aiming device can facilitate the percutaneous cannulated screwing for treatment of odontoid fractures of Anderson-D'Alonzo type Ⅱ and shallow type Ⅲ,given that it has advantages of simple manipulation,accurate insertion,minimal invasion,quick recovery and reliable efficacy.

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OBJECTIVE: To develop and test an arthroscopic aiming device for extra- to intra-articular femoral tunnel drilling emerging at the center of the femoral insertion of the cranial cruciate ligament (CrCL) in medium to large breed dogs. MATERIAL AND METHODS: Hindlimbs (n = 12) of six cadaveric dogs (≥ 20 kg bodyweight). One hindlimb from each cadaver was randomly chosen. On a standard medio-lateral stifle radiograph the caudo-cranial position of the CrCL center was measured and transferred onto an adjustable aiming device. After arthroscopic debridement of the CrCL the aiming device was hooked behind the lateral condyle and a 2.4 mm guide pin was placed from extra- to intra-articular. The intra-articular position of the resulting bone tunnel was evaluated radiographically as well as compared to the anatomic CrCl center of the contralateral hindlimb using 3D renderings. RESULTS: According to the postoperative radiographs all six drill tunnels were located at or near the CrCL center. The median absolute 3D error from the anatomical center of the CrCL was 0.6 mm (range: 0.2-0.9 mm). CONCLUSION: Precise anatomic placement of the femoral tunnel for intra-articular repair of the CrCL was achieved using an adjustable aiming device. CLINICAL RELEVANCE: The proposed technique will reduce femoral tunnel misplacement when performing intra-articular CrCL repair in dogs. In combination with the published technique for arthroscopic tibial tunnel drilling using a similar aiming device, the technical requirements for arthroscopic assisted tunnel positioning for anatomical graft replacement are available.

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