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Surgery combining stereotactically guided implantation of brain electrodes in subcortical key structures of the brain with the connection of these brain electrodes to subcutaneously implanted impulse generators is one precondition for the therapeutic application of deep brain stimulation (DBS). During the last 10-15 years minimal requirements concerning this surgery have been formulated, addressing in particular technical equipment and operational procedures and being also in parts supported quantitatively by systematic investigations. Only appropriate patient management, high technical standards and an adequate surgical technique can minimize the frequency of those complications, which are supposed to be directly caused by surgery. High-resolution imaging is the basis for target definition, determination of the surgical approach, documentation of final electrode position and postoperative exclusion of iatrogenic intracerebral haemorrhage. In addition, the quality of treatment planning depends largely on the image processing and viewing possibilities provided by specific planning software. Further issues, for which standards are defined, address electrophysiological and clinical examinations to be performed intraoperatively and general surgical measures, which should be considered during implantation of DBS systems. This review summarizes and evaluates requirements imposed on the aforementioned system components and working steps, taking into consideration data from the literature.

Cluster headaches involve a stereotypic symptomatic and belong to the most severe primary pain syndromes. Imaging studies have demonstrated functional and structural changes in the inferior-posterior hypothalamus ipsilateral to the pain. These changes are highly specific to the syndrome, strongly suggesting that this anatomical region is the trigger or generator of the acute attacks and/or determine the duration of the acute pain. These findings have led to the successful therapy of 19 not or difficult to treat patients with hypothalamic deep brain stimulation, resulting in long-term periods without pain and without significant side effects. Recently, however, a patient was reported who died after the operation due to increased blood pressure leading to the rupture of a previously non-diagnosed aneurysm. This article offers a translated summary of the recently published criteria of an international consensus group, which, in addition to a positive ethics vote, should be fulfilled before such deep brain stimulation of the hypothalamus is carried out in such patients.

The precise preoperative clinical and electrophysiological evaluation of the brachial plexus as well as an exact radiological evaluation are the keystones for the treatment of traumatic injuries of the brachial plexus. Furthermore, surgical management and prognosis of traction injuries of the brachial plexus depend on the accurate diagnosis of root avulsion from the spinal cord. Myelography, myelo-computed tomography and recently magnetic resonance imaging are the main radiological methods for preoperative diagnose of cervical root avulsions. Surgical experience shows that in may cases, extraspinal findings diverge from intradural findings. Consequently, only correlation with the intradural surgical findings will allow us to define the factual accuracy of myelo-CT and MRI studies. Accuracy of the preoperative myelo-CT based diagnosis related to the intraoperative intradural findings was 85% On the other hand, MRI showed an accuracy of only 52%. Therefore, myelo-CT scans with 1 to 3 mm axial slices proves to be the most reliable method to evaluate preoperatively the presence of complete or partial root avulsion in traumatic brachial plexus injuries. However in 15% of the cases preoperative exact radiological diagnosis is unfortunately not reliable. In these special cases intraspinal surgical exposure of the cervical roots will provide the accurate diagnosis of root avulsion. Accurate clinical evaluation and exact assessment of intraspinal root avulsion simplify enormously the decision concerning the choice of donor nerves for transplantation and/or neurotization during brachial plexus surgery.

The occurrence of sever pain is one of the most disabling symptoms after the traumatic lesion of the brachial plexus. Avulsion of one or more cervical roots of the brachial plexus is the main cause of severe pain, known as deafferentation pain. Lesion of the dorsal horn of the cervical spinal cord due to root avulsion may lead to important pathological changes and scarring that are responsible for the induction of pain sensations. Different medical and surgical treatment modalities have been established to relief such pain after brachial plexus injury. In contrast to drug therapy, which usually offers only limited benefit, surgical treatment over the last years has shown positive results. Coagulation of the dorsal root entry zone (DREZ) is one of the most efficient surgical treatments for these patients. Understanding of the pathophysiological changes and different pain mechanisms induced by traumatic injury of the brachial plexus is fundamental for the planning and step-wise treatment of such patients.

Neurotization procedures represent an important therapeutic option in patients with complete root avulsion due to traumatic brachial plexus injuries. A variety of normal donor nerves can be used, including intercostal nerves, accessory nerve, parts of the cervical plexus, phrenic nerve, and/or the contralateral C7 nerve root. The reconstructive neurotization procedure should be performed within 3-6 months following the trauma and, when successful, can lead to substantial improvement in motor function for the shoulder and upper arm and in sensory function for the forearm, hand and finger region. Neurotization can also be combined with neurolysis and/or transplantation to restore upper limb motor and sensory function in order to achieve greater therapeutic benefit for patients with posttraumatic brachial plexus lesions.

Autologous transplantation in brachial plexus injuries has become significantly more efficacious through increased knowledge of the microtopographic anatomy of the fascicle structures and the refinement of microneurosurgical techniques. Recovery of shoulder and upper arm functions can be achieved with autologous transplantation in the majority of patients under optimized conditions. However, attempts to restore forearm, hand and finger functions in this way have been disappointing so far. Therapeutic success is primarily governed by early decision making, selection of adequate surgical strategies and intensive and longlasting postoperative management.

The first results on functional effects induced by embryonic nigral grafts in the rat model of Parkinson's disease (PD) were reported in the late 70 s. It took another 10 years before the first publications on PD patients demonstrated clinical and neuroradiological signs of improvement after the transplantation of allogeneic embryonic nigral grafts. Technical details as well as clinical results varied considerably in the first clinical studies. In the last years crucial questions have been identified, also because of increasing international cooperation, which represent a challenge jointly to basic and clinical scientists. The clarification of those questions related to scientific and ethical issues will determine which impact the transplantation of embryonic nigral dopamine neurons will have as a potential therapy for PD in clinical medicine.