Somatostatin Receptor Subtype Expression in Patients with Acromegaly and Complicated Clinical Course.

Somatostatin analogues are considered to be the first line of treatment in acromegaly. Somatostatin analogues of the first generation mainly target the somatostatin receptor (SSTR) subtype 2 and have been proven efficient in the majority of patients with acromegaly. Pasireotide was the first somatostatin analogue also substantially targeting the SSTR subtype 5. An efficient drug for Cushing's disease tailored to suboptimal-responding patients with acromegaly then became available. We immunohistochemically investigated SSTR subtypes expression in pituitary adenomas from operated acromegaly patients with clinical relapse and a complicated clinical course. Patients received pasireotide in the course of their disease. The predictive value of SSTR subtypes immunhistochemical analysis for the therapeutic response is discussed.

Giant silent corticotrope pituitary adenoma in a patient with complicated clinical course.

Not required for Clinical Vignette.

Cerebrovascular biomodeling for aneurysm surgery: simulation-based training by means of rapid prototyping technologies.

OBJECTIVE: Opportunities for developing procedural skills are progressively rare. Therefore, sophisticated educational tools are highly warranted. METHODS: This study compared stereolithography and 3-dimensional printing for simulating cerebral aneurysm surgery. The latter jets multiple materials simultaneously and thus has the ability to print assemblies of multiple materials with different features. The authors created the solid skull and the cerebral vessels in different materials to simulate the real aneurysm when clipped. RESULTS: Precise plastic replicas of complex anatomical data provide intuitive tactile views that can be scrutinized from any perspective. Hollowed out vessel sections allow serial clipping efforts, evaluation of different clips, and clip positions. The models can be used for accurate prediction of vascular anatomy, for optimization of teaching surgical skills, for advanced procedural competency training, and for patient counseling. CONCLUSION: Simultaneous 3-dimensional printing is the most promising rapid prototyping technique to produce biomodels that meet the high demands of neurovascular surgery.

Prospective study on cranioplasty with individual carbon fiber reinforced polymer (CFRP) implants produced by means of stereolithography.

BACKGROUND: The aim of this study was to evaluate the value of carbon fiber reinforced polymer (CFRP) cranial implants produced by means of 3-dimensional (3D) stereolithography (SL) and template modeling for reconstructions of complex or extensive cranial defects. PATIENTS: A series of 41 cranioplasties with individual CFRP implants was performed in 37 patients between April 1996 and November 2002. Only patients with complex and/or large cranial defects were included, most of them having extended scarring or dural calcification and poor quality of the overlying soft-tissue cover after infection or multiple preceding operations. Involvement of frontal sinus, a known risk factor for complications after cranioplasty, was the case in 21 patients (51.2%). METHODS: A computer-based 3D model of the skull with the bony defect was generated by means of stereolithography after acquisition, evaluation and transfer of the patient's helical computed tomography (CT) data. A wax template of the defect that was used to design the individual prosthesis-shape was invested in dental stone. Then, the cranial implant was fabricated out of CFRP by loosen mold. RESULTS: Reconstruction of defects measuring up to 17 x 9 cm was performed. The intra-operative fit of the implants was excellent in 36 (87.8%), good in 1 (2.4%), and fair in 4 (9.8%) of the cases. Problems of implant fit occurred because of extended scarring and poor quality of soft-tissue cover. Adverse reactions were observed in 5 patients (1 subdural, 1 subcutaneous hematoma, 2 infections, 1 allergic reaction). Excellent contours and a solid stable reconstruction have been maintained in 30 out of 35 remaining plates (mean follow-up 3.6 years). No adverse effects concerning postoperative imaging, the accuracy of electroencephalograms and radiation therapy have been observed. CONCLUSIONS: The authors believe that this relatively new technique represents an advance in the management of complex and large cranial defects, but seems less suitable for simple defects because of cost-intensive techniques. Because of the high mechanical strength, biocompatibility, innovative design, and especially radiolucency, CFRP implants should, however, be considered in smaller defects if further imaging investigations or irradiation therapies are necessary.

Reduction of ischemic sequelae following spontaneous subarachnoid hemorrhage: a double-blind, randomized comparison of enoxaparin versus placebo.

BACKGROUND: Cerebral vasospasm, including its ischemic sequelae, remains a leading cause of death and disability following subarachnoid hemorrhage (SAH). This study was designed to evaluate whether the low-molecular-weight heparin (LMWH) enoxaparin reduces the occurrence of cerebral vasospasm and ischemia following spontaneous SAH. METHODS: A prospective, double-blind, randomized study was conducted in 120 consecutive patients with SAH (Hunt Hess Scale (HHS) I-III). Patients received one subcutaneous injection per day of either 20mg enoxaparin or placebo for 3 weeks following SAH. Efficacy endpoints were the occurrence of cerebral vasospasm, delayed ischemic deficit (DID), cerebral infarction, and overall outcome at 1 year following SAH. RESULTS: At 1-year follow-up, enoxaparin significantly reduced DID and cerebral infarction. Delayed ischemic deficit occurred in 8.8% of the enoxaparin group versus 66.7% of the placebo group (P<0.001), while 3.5% of vasospasm-related cerebral infarctions occurred in enoxaparin-treated patients and 28.3% in placebo-treated patients (P<0.001). Severe shunt-dependent hydrocephalus was significantly lower in the enoxaparin group (1.8% versus 16.7%; P=0.019). Compared with the placebo group, the enoxaparin group had fewer intracranial bleeding events and better overall outcomes at 1-year follow-up. Although there was potential bias as a result of patients in the placebo group being more severely affected (in terms of HHS), treatment with enoxaparin for 3 weeks improved long-term outcome following SAH. CONCLUSIONS: Enoxaparin is safe and effective in reducing cerebral vasospasm and ischemia following SAH (Hunt Hess grades I-III), resulting in a better long-term outcome for the patient.

Cerebrovascular stereolithographic biomodeling for aneurysm surgery. Technical note.

Stereolithographic (SL) biomodeling is a new technology that allows three-dimensional (3D) imaging data to be used in the manufacture of accurate solid plastic replicas of anatomical structures. The authors describe their experience with a patient series in which this relatively new visualization method was used in surgery for cerebral aneurysms. Using the rapid prototyping technology of stereolithography, 13 solid anatomical biomodels of cerebral aneurysms with parent and surrounding vessels were manufactured based on 3D computerized tomography scans (three cases) or 3D rotational angiography (10 cases). The biomodels were used for diagnosis, operative planning, surgical simulation, instruction for less experienced neurosurgeons, and patient education. The correspondence between the biomodel and the intraoperative findings was verified in every case by comparison with the intraoperative video. The utility of the biomodels was judged by three experienced and two less experienced neurosurgeons specializing in microsurgery. A prospective comparison of SL biomodels with intraoperative findings proved that the biomodels replicated the anatomical structures precisely. Even the first models, which were rather rough, corresponded to the intraoperative findings. Advances in imaging resolution and postprocessing methods helped overcome the initial limitations of the image threshold. The major advantage of this technology is that the surgeon can closely study complex cerebrovascular anatomy from any perspective by using a haptic, "real reality" biomodel, which can be held, allowing simulation of intraoperative situations and anticipation of surgical challenges. One drawback of SL biomodeling is the time it takes for the model to be manufactured and delivered. Another is that the synthetic resin of the biomodel is too rigid to use in dissecting exercises. Further development and refinement of the method is necessary before the model can demonstrate a mural thrombus or calcification or the relationship of the aneurysm to nonvascular structures. This series of 3D SL biomodels demonstrates the feasibility and clinical utility of this new visualization medium for cerebrovascular surgery. This medium, which elicits the intuitive imagination of the surgeon, can be effectively added to conventional imaging techniques. Overcoming the present limitations posed by material properties, visualization of intramural particularities, and representation of the relationship of the lesion to parenchymal and skeletal structures are the focus in an ongoing trial.