[Intralesional Cryosurgery in the Treatment of Keloids - A Differentiation of Keloid Types for the Improvement of Patient Selection]. / Keloidbehandlung mit intraläsionaler Kryochirurgie.

The overproduction of altered collagen fibers and the overexpression of Tumor Growth Factor-ß must be blocked in order to interrupt the growth process within a keloid scar. This can barely be achieved with the classical therapeutic methods. The results of keloid treatment are difficult to predict and the recurrence rate is usually over 50 %. In addition, some of the procedures used (e. g. irradiation) may induce additional health risks. Intralesional cryosurgery offers a therapeutic alternative that has been evaluated since more than a decade. Our own experience in more than one thousand keloid treatments allows a critical evaluation of the classification in those keloid types, which are recommended to be treated with the technique and those, which may not respond.

Cerebrovascular biomodelling: a technical note.

BACKGROUND: Recently computed tomographic angiography (CTA) and MR angiography (MRA) have been used to image cerebrovascular structures. Although CTA and MRA are accurate and sensitive imaging modalities, limitations have been identified in relation to image interpretation. Stereolithographic (SL) biomodelling is a new technology that allows three-dimensional (3D) CT and MR data to be used to accurately manufacture solid plastic replicas of anatomical structures. A prospective trial of SL biomodelling in cerebrovascular surgery has been performed to investigate the feasibility and clinical utility of this new display medium. METHODS: Fifteen patients with cerebral aneurysms and 1 patient with a cerebral arteriovenous malformation (AVM) were selected. 3D CT and/or MR angiograms were acquired and 19 solid anatomical biomodels manufactured using the rapid prototyping technology of stereolithography. The biomodels were used for patient education, diagnosis, operative planning and surgical navigation. RESULTS: The biomodels replicated the CTA and MRA source data. The accuracy of one biomodel was verified by comparison with a post mortem specimen, which corresponded exactly in the x and y planes but differed by 2 mm in the z plane. The ability to closely study an overview of complex cerebrovascular anatomy from any perspective on a solid biomodel was reported to enhance the surgeon's understanding, particularly when conventional images were equivocal. Cerebrovascular biomodels were found to be useful when positioning the patient's head for surgery, for selecting the best aneurysm clip and for the simulation of clipping. Patient informed consent was anecdotally improved. Disadvantages of the technology were the cost and manufacturing time. CONCLUSIONS: Cerebrovascular biomodelling may have utility in complex cases or when the standard imaging is felt to be equivocal.

Biomodel-guided stereotaxy.

OBJECTIVES: To simplify the practice of stereotactic surgery by using an original method, apparatus, and solid anatomic replica for trajectory planning and to validate the method and apparatus in a laboratory and clinical trial. METHODS: The patient is marked with fiducials and scanned by using computed tomography or magnetic resonance imaging. The three-dimensional data are converted to a format acceptable to stereolithography. Stereolithography uses a laser to polymerize photosensitive resin into a solid plastic model (biomodel). Stereolithography can replicate blood vessels, soft tissue, tumor, and bone accurately (<0.8 mm). A stereotactic apparatus is referenced to fiducials replicated in the biomodel. The trajectory for the intervention is determined and saved. The apparatus is attached to the patient fiducials, and the intervention is replicated. RESULTS: Three types of apparatus (template, Brown-Roberts-Wells frame, and D'Urso frame) were tested on phantoms and patients requiring the excision/biopsy of tumors. The localization errors determined from the phantom studies were template, 0.82 mm; Brown-Roberts-Wells frame, 1.17 mm; and D'Urso frame, 0.89 mm. The surgeons reported that clinical use of the template and D'Urso frame was accurate and ergonomic. The Brown-Roberts-Wells frame was more difficult to use and somewhat inaccurate. CONCLUSION: Biomodel-guided stereotaxy has significant advantages. It is performed quickly; it is based on simple, intuitive methodology; it enhances visualization of anatomy and trajectory planning; it enhances patient understanding; it uses inexpensive equipment; it does not require rigid head fixation; and it has greater versatility than known techniques. Disadvantages are biomodel cost and a manufacturing time of 12 to 24 hours.

Trigeminal neuralgia. Surgical treatment by microvascular decompression of the trigeminal nerve root.

The surgical management of trigeminal neuralgia has always been less than ideal. Evidence accumulated over the last 10 years suggests that the condition is caused by vascular compression of the trigeminal nerve root at the brain stem. Removal of this compression by means of micro-neurosurgical techniques has so far been very effective in relieving the pain of trigeminal neuralgia while maintaining normal facial sensation. A series of 10 patients who underwent this procedure is presented. All patients lost their pain, and during the follow-up period of six to 18 months, there have been no recurrences. This experience further demonstrates that the microvascular decompression is a very useful procedure in selected patients.

Surgical relief of post-herpetic pain by excision of scarred skin.

This paper deals with the problems of post-herpetic pain. The various modes of treatment which have been tried for its relief are discussed as is our experience of excision of the scarred area of skin. The procedure has been found to offer worthwhile pain relief to a significant number of patients.

Ascites from a ventriculoperitoneal shunt.

An unusual case of ascites secondary to a ventriculoperitoneal shunt is presented. The ascites did not redevelop following diversion of the distal catheter into the right atrium, and no adequate explantation was found as to why the cerebrospinal fluid was not absorbed by the peritoneum.