CONCLUSION: The preoperative three-dimensional (3D) modeling of the pituitary adenoma together with pituitary gland, optic nerves, carotid arteries, and the sphenoid sinuses was adopted for routine use in our institution for all pituitary surgery patients. It gave the surgeon a more profound orientation to the individual surgical field compared with the use of conventional 2D images only. OBJECTIVE: To demonstrate the feasibility of 3D surgical planning for pituitary adenoma surgery using readily available resources. SUBJECTS AND METHODS: The computed tomography (CT) and magnetic resonance imaging (MRI) data of 40 consecutive patients with pituitary adenoma were used to construct 3D models to be used in preoperative planning and during the surgery. A freely available, open source program (3D Slicer) downloaded to a conventional personal computer (PC) was applied. RESULTS: The authors present a brief description of the 3D reconstruction-based surgical planning workflow. In addition to the preoperative planning the 3D model was used as a 'road map' during the operation. With the 3D model the surgeon was more confident when opening the sellar wall and when evacuating the tumor from areas in contact with vital structures than when using only conventional 2D images.
The standard workflow in many image-guided procedures, preoperative imaging followed by intraoperative registration, can be a challenging process and is not readily adaptable to certain anatomical regions such as the wrist. In this study we present an alternative, consisting of a preoperative registration calibration and intraoperative navigation using 3D cone-beam CT. A custom calibration tool was developed to preoperatively register an optical tracking system to the imaging space of a digital angiographic C-arm. This preoperative registration was then applied to perform direct navigation using intraoperatively acquired images for the purposes of an in-vitro wrist fixation procedure. A validation study was performed to assess the stability of the registration and found that the mean registration error was approximately 0.3 mm. When compared to two conventional techniques, our navigated wrist repair achieved equal or better screw placement, with fewer drilling attempts and no additional radiation exposure to the patient. These studies suggest that preoperative registration coupled with direct navigation using procedure-specific graphical rendering, is potentially a highly accurate and effective means of performing image-guided interventions.
The advantages and limitations of image guidance systems for endoscopic sinus surgery are unclear. We report our experience and present a meta-analysis of the evidence.
We performed a retrospective analysis of endoscopic sinus surgery procedures performed with versus without image guidance. A total of 355 cases was included. Primary outcomes included complication rates and time to revision surgery. A literature search was conducted to enable identification and analysis of studies of similar comparisons.
Within 1.5 years of the index sinus surgical procedure, the risk of revision surgery was significantly higher for patients treated with non-assisted versus computer-assisted endoscopic sinus surgery (p = 0.001). Meta-analysis did not indicate a reduction in complications or revision surgery procedures with the use of image guidance systems, although the majority of included studies showed a non-significant reduction in revision surgery.
Our study offers some evidence that computer-assisted endoscopic sinus surgery may delay residual disease and reduce the requirement for revision surgery. Although this finding was not borne out in the meta-analysis, the majority of identified studies demonstrated a trend towards fewer revision procedures after computer-assisted endoscopic sinus surgery. This type of surgery may offer other advantages that are not easily measurable.
Gamma Knife radiosurgery (GKRS) has been established as a safe and effective treatment option for trigeminal neuralgia. Some patients have contraindications to magnetic resonance imaging (MRI), the standard stereotactic imaging used for GKRS treatment planning. Computerized tomography (CT) imaging may be used as an alternative in this scenario. We sought to evaluate the outcomes of our patients treated using this technique.
Between August 2001 and November 2009, 19 patients with trigeminal neuralgia were treated with GKRS using CT-only planning. The course of the trigeminal nerve was determined based upon anatomical landmarks when the nerve was not directly visualized on the treatment-planning CT. Median dose used was 90 Gy (range 85-90 Gy). Follow-up data based on Barrow Neurological Institute (BNI) pain score and toxicity were obtained using electronic medical records and by telephone interview.
With median follow-up time of 18 months (range 4-36 months), improvement in quality of life after GKRS was reported in 17 of 19 patients. Freedom from BNI IV-V pain relapse was 82% at 24 months. By 3 months post-GKRS, 50% of patients were able to discontinue medications completely. Three patients reported numbness after GKRS; none of these patients described bothersome numbness. Use of contrast did not affect treatment outcome (P = 0.31).
Stereotactic CT-only treatment planning of GKRS for the treatment of trigeminal neuralgia is feasible and safe. Further studies are necessary to determine if the long-term durability of pain relief is comparable to that of MRI-based GKRS planning.
To review retrospectively initial experience at a single institution using frameless image-guided radiosurgery (IGRS) for trigeminal neuralgia employing the Novalis linear accelerator (LINAC) with ExacTrac robotic patient positioning device.
Over an 18-month period, 44 patients (27 women and 17 men; median age 65 years) were treated with frameless IGRS for typical trigeminal neuralgia (14 cases involved left-sided pain and 30 cases involved right-sided pain), responsive to anticonvulsant medications, with Barrow Neurological Institute Pain Scale (BNI-PS) scores of 4 or 5. All cases were initial radiosurgery treatments with an isocenter dose of 90 Gy delivered via a 4-mm circular collimator forming a spheroid dose envelope. Intrafraction positioning data were collected for all patients. The median follow-up was 15 months.
Overall intrafraction positioning error was 0.49 mm ± 0.44. After treatment, 40 patients achieved a BNI-PS score of IIIb or better; 19 patients achieved a BNI-PS score of I. The median time to pain relief was 4 weeks. Overall, new hypoesthesia was seen in five patients. No other complications were seen.
Use of frameless IGRS methods for treatment of trigeminal neuralgia showed results similar to the authors' prior experience with frame-based treatment methods. IGRS using frameless methods is a suitable treatment method for patients with trigeminal neuralgia and may be applicable to other functional indications.
Comment In: World Neurosurg. 2010 Oct-Nov;74(4-5):45121492593
Comment In: World Neurosurg. 2010 Oct-Nov;74(4-5):448-5021492592
Thermotherapeutic tools are increasingly used for tissue ablation, although the intra-operative monitoring is not adequate for such procedures. This is a main challenge for more extensive use of any ablative technique. The present work focuses on treatment of hepatic tumours by cryo therapy. For any thermotherapeutic tool there are specific thermal conditions that have to be met to ensure treatment adequacy. A software tool was made to calculate and visualise 3D temperature distributions during hepatic cryoablation combined with a 3D intra-operative navigation system. This system aids the user in placing the cryoprobe using an optical tracking system and 3D visualisation of the probe placement in relation to the target anatomy and the planned trajectory. 3D temperature distributions are calculated and visualized intra-operatively. The system is integrated with an interventional Magnetic Resonance 0.5T scanner. The system was tested in an animal experiment, exemplifying the usefulness of the navigation system and its ability to give intuitive feedback to the user on thermodynamic conditions induced in the target region. The system constitutes a novel tool for enhanced intra-operative control during cryoablative procedures, and motivates for studies using this tool to investigate predictors applied as indicators of treatment adequacy and patient outcome.
OBJECTIVE: The objective of this study is to introduce a new radiosurgical device, the Leksell Gamma Knife Perfexion (Elekta Instruments AB, Stockholm, Sweden). Design and performance characteristics are compared with previous models of the gamma knife in a clinical setting. METHODS: Performance-related features in the design of the new radiosurgical system are described, and the ability to create complex shapes of isodose volumes even with a single isocenter is demonstrated. The concept of "dynamic shaping" of dose distribution is introduced as a means of decreasing the exposure to structures outside the target. Dose plans for the Leksell Gamma Knife Models B, 4C, and Perfexion have been created for target pathologies to illustrate how the software and hardware of the new radiosurgical system can increase treatment quality, decrease treatment time, and increase patient comfort. Radiation doses to critical organs in the rest of the human body are compared. RESULTS: The automated collimator arrangement in the Perfexion makes it possible to produce more complex treatment volumes than with previous models of the gamma knife. This results from the enhanced ability to shape isodose volumes, even for single isocenters. The collimator arrangement and the patient positioning system also allow shorter patient transit times, reducing unwanted radiation exposure during movement between isocenters. CONCLUSION: The Perfexion exceeds the capabilities of previous gamma knife models in terms of treatment efficiency, conformity, and radiation protection. These qualities enable treatment of larger target volumes, especially close to eloquent areas. Pathologies previously inaccessible in the head and neck are now treatable due to the increased volume of the radiation cavity.
BACKGROUND: An important factor for patient satisfaction after cataract surgery is the achievement of the planned target refraction. The formulae which are used to calculate the necessary refractive power of the intraocular lens (IOL) to be implanted have been improved over time in order to deliver exact predictions even in those cases in which the measurements of an eye deviate greatly from the norm. We examined which of the routinely measured biometric values have an influence on reaching target refraction. PATIENTS AND METHODS: This retrospective investigation reports on a case series of 153 eyes of 146 patients within 6 months in which a cataract operation was performed. The average age at the time of operation was 73.5 years. Four measurements were taken preoperatively: refraction (Ref), axial length (AL), corneal refractive power (CR) and anterior chamber depth (ACD). Each of these measurements was examined regarding its influence on the refractive outcome. One of three end points was possible for each eye: achievement of target refraction within +/- 0.5 dpt, aberrance from target refraction by more than + 0.5 dpt and aberrance from target refraction by more than - 0.5 dpt. A multivariate regression analysis was performed in which aberrance from target refraction was defined as the dependent variable and the four mentioned measurements were set as independent variables. RESULTS: Of the 153 eyes, in 91 eyes the target refraction was achieved within 0.5 dpt (group 1). In 37 eyes the aberrance from target refraction was more than - 0.5 dpt (group 2) and in 25 eyes it was more than + 0.5 dpt (group 3). The mean measurement values in groups 1, 2 and 3 were as follows: for preoperative refraction 0.0 dpt/0.5 dpt/0.625 dpt, for corneal refractive power 42.84 dpt/42.29 dpt/42.67 dpt, for axial length 23.41 mm/23.36 mm/23.73 mm and for anterior chamber depth 3.07 mm/3.00 mm/3.20 mm. No statistically significant relation between the respective measured values or a combination thereof and the refractive result could be demonstrated. CONCLUSIONS: The formulae for calculating IOL power available today are highly developed and integrate preoperative biometries in a non-linear way, so that there is little difference between measurements within the norm and outlying ones concerning their influence on the refractive result. When conducting quality assurance efforts, we recommend to direct attention to factors influencing anterior chamber depth.
To evaluate the effect of the learning curve on operative, postoperative, and pathological outcomes of the first 67 totally intracorporeal robot-assisted radical cystectomies (RARCs) with neobladders performed by two lead surgeons at Karolinska University Hospital.
Between December 2003 and October 2012, 67 patients (61 men and six women) underwent RARC with orthotopic urinary diversion by two main surgeons. Data were collected prospectively on patient demographics, peri- and postoperative outcomes including operation times, conversion rates, blood loss, complication rates, pathological data and length of stay (LOS) for these 67 consecutive patients. The two surgeons operated on 47 and 20 patients, respectively. The patients were divided into sequential groups of 10 in each individual surgeon's series and assessed for effect of the learning curve.
Patient demographics and clinical characteristics were similar in both surgeons' groups. The overall total operation times trended down in both surgeons' series from a median time of 565 min in the first group of 10 cases, to a median of 345 min in the last group for surgeon A (P