[Haemorrhage in arteriovenous malformations of the brain following radiosurgery: the importance of the latency period]. / Hemorragia de las malformaciones arteriovenosas cerebrales tras la radiocirugía: importancia del período de latencia.

INTRODUCTION: Arteriovenous malformations are abnormal communications between arteries and veins. Treatment can consist in surgery, embolisation and/or radiosurgery. AIM: To assess the influence of radiosurgery on the risk of bleeding and related factors. PATIENTS AND METHODS: Retrospective study of 79 patients who were treated with a 6 MV linear accelerator. Clinical, morphological and dosimetric parameters were collected and a statistical analysis was performed to investigate their relationship with bleeding during the latency period. RESULTS: The mean age was 33.7 years, and 56% of patients were females. The mean volume was 6.16 cm(3). Bleeding occurred before treatment in 52.6% of cases. Altogether 25% had been embolised and 7.6% had been treated earlier using radiosurgery. Six patients suffered a haemorrhage after treatment. Bleeding occurred in 21% of those who had undergone embolisation versus 3.6% in non-embolised individuals (p < 0.02). Bleeding occurred in 33.3% of those who had been treated radiosurgically on more than one occasion, and only 5.7% if they were treated just once (p = 0.02). Bleeding took place in 28.6% of lesions above 10 cm(3) and in 3.2% when they were smaller (p < 0.01). Bleeding occurred in 16.1% of patients if they received less than 17 Gy, and in 2.22% if they received 17 or more (p < 0.01). All haemorrhages took place in treatments with more than one isocentre (p < 0.01) and with a higher homogeneity index (p < 0.01). CONCLUSIONS: Radiosurgery does not modify the risk of bleeding. The factors associated to higher percentages of bleeding are also related to poorer closure outcomes and longer latency periods.

Update on the Cloward procedure: new instruments.

A series of 283 patients who suffered from cervical spondylosis, herniated disc, or traumatic pathology of the cervical spine were operated on using an anterior approach. Intersomatic arthrodesis was performed in 350 cases; in every case, a threaded bone graft was screwed into the intervertebral orifice using the technique described by the author. Fusion was achieved within 6 months in 93% of cases with 92 autologous grafts and in 81% of cases with 258 heterologous grafts. In addition to the use of threaded intervertebral holes and threaded bone grafts, the Cloward technique was modified by the introduction of a set of new instruments, which largely replaced the ones previously use. These included a low-speed motor with different drills and trephines, a trephine guide retractor, and an intersomatic retractor.

Anterior cervical interbody fusion with threaded cylindrical bone.

The author describes some modifications of the original Cloward method of cervical intervertebral body fusion. These modifications include the intraoperative threading of the standard cylindrical graft dowel (either autologous or heterologous) and the development of two new instruments designed to insert the graft into the intervertebral space. This modified technique was tested in an experimental study using the cervical spine of cadavers, after which a series of 37 patients were operated on with this method. The results of both series are presented. The chief advantages of this type of interbody fusion over the standard technique are: 1) easier insertion of the graft into the intervertebral space; and 2) decrease in complications. Complications with cervical interbody fusion, both minor (such as partial displacement of the graft, vertebral angulation, and radicular injury) and major (such as spinal cord compression and/or contusion), are fortunately infrequent, but they are important because of their irreparable consequences.