A novel method of neurophysiological brainstem mapping in neurosurgery.

BACKGROUND: Brainstem mapping with electrical stimulation allows functional identification of neural structures during resection of deep lesions. Single pulses or train of pulses are delivered to map cranial nerves and corticospinal tracts, respectively. NEW METHOD: We introduce a hybrid stimulation technique for mapping the brainstem. The stimulus consists of an electrical single pulse followed by a short train of 3-5 pulses at 500 Hz, at an interval of 60-75 ms. The responses to this stimulation pattern are recorded from appropriate cranial and limb muscles. RESULTS: Both the single pulse and the short train elicit electromyographic responses when motor fibers or motor nuclei of the cranial nerves are stimulated. Responses to the train but not to the preceding single pulse indicate activation of the descending motor tracts, in the mesencephalon and the pons. Conversely, in the medulla, limb responses to stimulation of the corticospinal tracts are elicited by a single pulse. Identification of the extra and intra-axial courses of the trigeminal motor and sensory fibers is possible by recording responses from the masseter and the tongue muscles. COMPARISON WITH EXISTING METHOD(S): To date, either a pulse or a train is delivered during brainstem mapping, switching from one to the other modality according to the expected target structure. This procedure can be time-consuming and may even lead to false negative responses to the stimulation, eventually leading to inaccurate neurosurgical procedures. CONCLUSIONS: The novel hybrid pulse-train technique enhances the advantage of brainstem mapping procedure, minimizing pitfalls and improving patient safety.

Management of post blood patch severe rebound intracranial hypertension by the usage of an external ventricular drain.

Spontaneous intracranial hypotension (SIH) is a condition characterised by postural headaches due to low cerebrospinal fluid (CSF) pressure, often stemming from CSF leakage. Diagnosis poses a significant challenge, and the therapeutic approach encompasses both conservative measures and operative interventions, such as the epidural blood patch (EBP). However, EBP carries the potential risk of inducing rebound intracranial hypertension (RIH), subsequently leading to high-pressure headaches. We present a case wherein RIH following EBP was effectively managed through the implementation of an external ventricular drain (EVD) aimed at reducing CSF pressure. The patient improved significantly, underscoring the potential utility, if not necessity, of EVD in carefully selected cases, highlighting the imperative for further research to enhance the management of SIH and optimise EBP-related complications.

Surgical Treatment of Complex Craniofacial Fractures.

OBJECTIVE: Severe craniofacial fractures may present different needs in treating intracranial lesions over facial injuries. This paper examines the results of our strategy, consisting of a single-stage combined neurosurgical-maxillofacial treatment. METHODS: A retrospective review was conducted of 33 consecutive patients with complex fractures of the anterior cranial fossa and facial skeleton, who required elective surgery for craniofacial reconstruction. Patients who required emergency surgery for intracranial clots or penetrating wounds were excluded. In all cases, all or almost all the anterior skull-base was injured with compound fractures of the frontal sinus, the orbital roofs, the lamina cribrosa, and the planum sphenoidale. In all cases, the prioritization of treatment was carefully discussed, and surgical timing and strategy were agreed. RESULTS: There was 1 dead. Olfactory injuries were always found intraoperatively. There were no mucoceles, CSF-leak recurrences, cranial infections, or neurologic worsening. The functional and neurologic results were highly satisfactory. CONCLUSIONS: The one-stage surgical treatment of complex craniofacial fractures has numerous advantages, including the possibility of reducing facial fractures without the risk of CSF leaks. It also eliminates the need for repeated procedures in fragile patients, and the need to dismantle the facial reconstruction if the skull base repair is performed later. The main issue is the surgical timing, considering that the maxillofacial surgeon usually favors early facial repair, whereas the neurosurgeon generally prefers delayed manipulation of the contused frontal lobes. A timeframe of 10-14 days after trauma may be a good compromise for safe procedures with excellent neurologic and functional outcomes.

Reoperation in Chiari-1 Malformations.

(1) Background: The issue of unsuccessful surgery for Chiari-1 malformation (CM-1), as well as its potential causes and possible solutions, remains poorly documented and studied. (2) Methods: From a retrospective review of a personal series of 98 patients undergoing treatment for CM-1 during the past 10 years, we created two study groups. Group 1: 8 patients (8.1%) requiring additional surgeries owing to postoperative complications (7 cerebrospinal fluid leakage, 1 extradural hematoma); 7 patients (7.1%) undergoing reoperations for failed decompression during the follow-up. Group 2: During the same period, we also managed 19 patients who had previously been operated on elsewhere: 8 patients who required adequate CM-1 treatment following extradural section of the filum terminale; 11 patients requiring reoperations for failed decompression. Failed decompression was managed by adequate osteodural decompression, which was associated with tonsillectomy (6 cases), subarachnoid exploration (8 cases), graft substitution (6 cases), and occipito-cervical fixation/revision (1 case). (3) Results: There was no mortality or surgical morbidity in Group 1. However, one patient's condition worsened due to untreatable syrinx. In Group 2, there were two cases of mortality, and surgical morbidity was represented by functional limitation and pain in the patient who needed revision of the occipitocervical fixation. Twenty patients improved (58.8%), 6 remained unchanged (32.3%), 1 worsened (2.9%) and 2 died (5.9%). (4) Conclusions: The rate of complications remains high in CM-1 treatment. Unfortunately, a certain rate of treatment failure is unavoidable, but it appears that a significant number of re-operations could have been avoided using proper indications and careful technique.

Revision surgery for degenerative spinal deformity: a case report and review of the literature.

INTRODUCTION: Management of spinal degenerative deformities always represents a challenge for the spinal surgeon. CASE PRESENTATION: We report a case of revision surgery for adult scoliosis, focusing of most common errors in pre-surgical management and criteria for reoperation. We analyzed the spino-pelvic parameters on the standing whole-spine X-ray and the role of sagittal balance. To restore 45° of lumbar lordosis, we performed a L3 Pedicle Subtraction Osteotomy (PSO), along with L2-L3 and L3-L4 eXtreme Lateral Interbody Fusion (XLIF). DISCUSSION: In cases of adult scoliosis, careful preoperative planning is necessary in an attempt to avoid difficult, expensive, and high-risk additional procedures.