Predictors of ventricular tension pneumocephalus after posterior fossa surgery in the sitting position.

BACKGROUND: Ventricular pneumocephalus is a rare but potentially life-threatening complication of cranial surgery in the sitting position. OBJECTIVE: The objective of the study is to assess the incidence and risk factors of postoperative ventricular pneumocephalus. METHODS: We performed a retrospective chart review of 307 consecutive patients (147 men, 160 women) treated at our institution by intracranial surgery in the sitting position from January 2010 to October 2014. Ventricular air entrapment with lack of arousal or neurologic deterioration requiring external ventriculostomy (EVD) was defined as ventricular tension pneumocephalus (VTP). Demographic variables were recorded along with radiological and clinical data. The occurrence of pneumocephalus was correlated with patient-related and surgical variables. RESULTS: VTP was observed in 12 cases (3.9%). These patients had higher intraventricular air volumes (48.5 cm3 (CI 95% [29.06-67.86])) compared to asymptomatic patients (7.4 cm3 (CI 95% [5.43-9.48])). Opening of the fourth ventricle was the most potent predictor of VTP (OR = 34.7, CI 95% [4.4-273.5], p = 0.001). In patients undergoing no additional treatment for pneumocephalus, ventricular air volume declined to an average of 41.7% of the initial postoperative volume on postoperative day 3. CONCLUSIONS: Entrapment of intracranial and particularly ventricular air requiring emergent EVD occurred in 3.9% cases of intracranial surgery in the sitting position. Especially the opening of the fourth ventricle was associated with the development of VTP, which should warrant particularly diligent postoperative observation of these patients. In cases without neurological symptoms, the rate of spontaneous air resorption is sufficiently high to warrant expectant management.

Contrast-enhanced shunt series ("shuntography") compare favorably to other shunt imaging modalities in detecting shunt occlusion.

BACKGROUND: Obstruction is a common cause of ventriculo-peritoneal shunt failure. Head computed tomography and plain x-ray examinations of shunt tubing ("shunt series") are routinely used in patients readmitted for reemerging symptoms but are of limited value. The validity of shunt series can be improved by applying contrast agent into the system (contrast-enhanced shunt series, a.k.a. a "shuntogram" or "shuntography"). We hypothesized that contrast-enhanced shunt series have a high predictive value for shunt revision surgeries. METHODS: We retrospectively re-evaluated 107 contrast-enhanced shunt series and reviewed the patient histories. We defined outcome parameters for calculating the utility of a pathological contrast-enhanced shunt series in predicting revision surgery. RESULTS: Of 107 contrast-enhanced shunt series, 41 examinations were positive for obstruction, mainly of the ventricular (36.5 %) and the peritoneal catheter (48.8 %). Within 30 days, 35 successful revision surgeries and 3 revision surgeries without resolution of symptoms were performed. In two cases the shunt tubing was found to be patent. Sixty-six negative examinations resulted in two revision surgeries, in addition to ten surgeries not attempting to restore patency. After 30 days, the specificity of contrast-enhanced shunt series for shunt failure identification was calculated at 92.8 %, the sensitivity at 94.7 %, the positive predictive value at 87.8 %, and the negative predictive value at 97.0 %. CONCLUSIONS: The contrast-enhanced shunt series method is a highly specific examination with a negative predictive value exceeding that of head computed tomography and plain shunt series. Compared to radionuclide marker studies, contrast-enhanced shunt series demonstrate better spatiotemporal resolution, enabling focused local surgical repair.

Asphyxia due to laryngeal spasm as a severe complication of awake deep brain stimulation for Parkinson's disease: a case report.

BACKGROUND: In accordance with German neurosurgical and neurological consensus recommendations, lead placements for deep brain stimulation (DBS) in patients with Parkinson's disease (PD) are usually performed with the patient awake and in "medication off" state. This allows for optimal lead position adjustment according to the clinical response to intraoperative test stimulation. However, exacerbation of Parkinsonian symptoms after withdrawal of dopaminergic medication may endanger the patient by inducing severe "off" state motor phenomena. In particular, this can be a problem in awake craniotomies utilizing intraoperative airway management and resuscitation. CASE PRESENTATION: We report the case of a PD patient with progressive orofacial and neck muscle dystonia resulting in laryngeal spasm during DBS lead placement. This led to upper airway compromise and asphyxia, requiring resuscitation. CONCLUSIONS: Laryngeal spasms may occur as a rare "off" state motor complication in patients with PD. Other potential causes of intraoperative difficulties breathing include bilateral vocal cord palsy, positional asphyxia, and silent aspiration. In our practice, we have adjusted our medication regimen and now allow patients to receive their standard dopaminergic medication until the morning of surgery. Neurologists and neurosurgeons performing lead placement procedures for PD should be aware of this rare but unsafe condition to most optimized treatment.

Use of closed suction devices and other drains in spinal surgery: results of an online, Germany-wide questionnaire.

PURPOSE: The risks of drains in spine surgery (e.g., increasing venous plexus bleeding, maintaining CSF leakage, and infections) must be balanced with their benefits (e.g., reduced rate of postoperative hematoma and seroma formation). Little is known about factors that influence surgeons' decision to employ a drain. METHODS: We conducted a survey among German spine surgeons regarding their use of drains. Neurosurgical and orthopedic departments along with privately practicing neurosurgeons were invited to complete an online questionnaire featuring general and case-specific questions with regard to drain placement. RESULTS: We received 163 questionnaires (private practice and small-volume centers 36.1%, medium- and large-volume centers 43.6%, university centers 20.2%). Factors influencing the decision to use a drain include size of wound, type of procedure, hemostasis at the end of the procedure, and coagulopathies; factors found to be less important include overall blood loss, body mass index, and implants. 31% of surgeons will use drains for microdiskectomies. For other pathologies, percentages are as follows: anterior cervical diskectomy and fusion, 58%; cervical laminoplasty, 62%; hemilaminectomy for bisegmental lumbar stenosis, 69%; transpedicular instrumentation, 88%; vertebral body replacement for metastasis, 94%. Over half of those who usually employ a drain will not use a drain in cases of unintentional durotomy. CONCLUSION: In terms of indication, duration, and safety measures, use of drains in spinal surgery is heterogeneous. The majority of surgeons prefer drains to suction in most cases, except for microdiskectomies, for which only 31% will use a drain. Nearly all colleagues discontinue drains by day 4.

Unnecessary dental procedures as a consequence of trigeminal neuralgia.

Trigeminal neuralgia (TN) is a disorder characterized by repetitive lancinating pain along one or more branches of the trigeminal nerve and is commonly triggered by chewing and manipulation of the gums. The second and third divisions are most commonly affected. Due to these symptoms, patients are likely to consult their local dentist when symptoms first develop and may receive further dental evaluation and treatment before they are referred to a neurologist or neurosurgeon. We sought to answer questions regarding evaluation and possible dental treatment as well as referral patterns in TN patients. Using a surgical database, we obtained data of patients undergoing an intervention for trigeminal neuralgia. Telephone interviews were conducted, focusing on initial evaluation and possible dental treatment, on referral patterns, and on present status. Secondly, a written questionnaire was mailed to local dentists. Eighty-two percutaneous rhizotomies and 33 microvascular decompressions were performed in 99 trigeminal neuralgia patients. Of 92 patients contacted, 51 were alive and willing to participate. Two thirds reported being pain-free. Forty-one patients (82%) initially consulted their dentist; of these, 27 patients received invasive dental treatment for the pain syndrome, including extractions, root canal treatments, and implants. Of 98 local dentists contacted, 51 responded, with three quarters feeling competent in evaluating trigeminal neuralgia. A high percentage of patients that are surgically treated for trigeminal neuralgia consult their dentist first and receive possibly unjustified dental treatment. Differential diagnoses include odontogenic pain syndromes as well as atypical orofacial pain. The present literature acknowledges difficulties in correctly diagnosing trigeminal neuralgia, but seems to underestimate the extent.

Augmented Reality-Supported Rod Bending in Multilevel Spinal Fusion Using the ADVISE Software.

BACKGROUND: One of the most common reasons for poor patient outcomes and revision surgery in spinal fusion is hardware failure. Screw loosening or pullout occurs in up to one-quarter of all cases. It is known that even small screw-rod misalignments can cause significant mechanical overloads during rod fixation, which can result in hardware failure. To address this crucial surgical step, a novel augmented reality-assisted software was developed to generate custom rod templates that are precisely adapted to the individual patient. METHODS: The novel software, which runs on a tablet, is used in spinal fusion surgery and is based on the use of a specific pedicle screw system, in which the polyaxial screw heads are connected to detachable guides. These guides can be recognized by the tablet camera and a light detection and ranging scanner. This image information is processed to determine the spatial positions of the screw heads and to calculate an ideally fitting rod template. RESULTS: The calculated rod template is displayed in a 1-to-1 scale on the tablet screen. This template is used to cut and bend the rods of the pedicle screw system. Finally, the custom bent rod can be inserted into the screw heads without tension. CONCLUSIONS: The augmented reality-assisted software is intended to give surgeons access to patient-specific intraoperative real-time data, helping them in bending rods that are more precisely adapted to the individual patient compared with the freehand technique.

The role of intraoperative microelectrode recording and stimulation in subthalamic lead placement for Parkinson's disease.

OBJECTIVE: Intraoperative microelectrode recording (MER) and test-stimulation are regarded as the gold standard for proper placement of subthalamic (STN) deep brain stimulation (DBS) electrodes in Parkinson's disease (PD), requiring the patient to be awake during the procedure. In accordance with good clinical practice, most attending neurologists will request the clinically most efficacious trajectory for definite lead placement. However, the necessity of microelectrode-test-stimulation is disputed, as it may limit the access to DBS therapy, excluding those not willing or incapable of undergoing awake surgery. METHODS: We retrospectively analyzed the MERs and microelectrode-test-stimulation results with regard to the decision on definite lead placement and clinical outcome in a cohort of 67 PD-patients with STN-DBS. All patients received bilateral quadripolar ring electrodes. To ascertain overall procedural efficacy, we calculated the surgical index (SI) by comparing preoperative motor improvement induced by levodopa to that induced by stimulation 7 to 18 months after surgery, measured as the relative difference between ON and OFF-states on the Unified Parkinson's Disease Rating Scale motor part (UPDRS-3). Additionally, a side-specific surgical index (SSSI) was calculated using the unilateral assessable items of the UPDRS-3. The SSSI where microelectrode-test-stimulation overruled MER were compared to those where the result of microelectrode-test-stimulation was congruent to MER results. RESULTS: A total of 134 electrodes were analyzed. For final lead placement, the central trajectory was chosen in 54% of patient hemispheres. The mean SI was 0.99 (± 0.24). SSSI averaged 1.04 (± 0.45). In 37 lead placements, microelectrode-test-stimulation overruled MER in the final trajectory selection, in 27 of these lead placements adverse effects during microelectrode-test-stimulation were decisive. Neither the number of test electrodes used nor the STN-signal length had an impact on the SSSI. The SSSI did not differ between lead placements with MER/microelectrode-test-stimulation congruency and those where the results of microelectrode-test-stimulation initiated lead placement in a trajectory with shorter STN signal. CONCLUSION: Intraoperative testing is mandatory to ensure an optimal motor outcome of STN DBS in PD-patients when using quadripolar ring electrodes. However, we also demonstrated that neither the length of the STN-signal on MER nor the number of test electrodes influenced the motor outcome.

Enlightening the Cerebellopontine Angle: Intraoperative Indocyanine Green Angiography in Microvascular Decompression for Trigeminal Neuralgia.

Background and Study Aims In microvascular decompression of the trigeminal nerve for trigeminal neuralgia (TN), the site of conflict is occasionally difficult to identify. Endoscopy has been described to better evaluate the anatomical conflict in such situations. We hypothesized that indocyanine green (ICG) angiography could allow for better visualization of the compressing artery and its anatomical relation to the nerve. Material and Methods ICG angiography was performed in 17 TN patients undergoing microvascular decompression. We focused on whether ICG angiography is helpful in determining the site of conflict, particularly when not directly visible via the microscope, and whether fluorescence is strong enough to shine through the nerve obliterating the direct view of the compressing vessel. Results In four patients, the site of conflict was immediately apparent after opening the cerebellopontine cistern, and ICG angiography did not provide the neurosurgeon with additional information. In another two patients, imaging quality and fluorescence were too poor. Of the remaining 11 patients with a hidden site of nerve-vessel conflict, ICG angiography was found to be helpful in anticipating the site of compression and the course of the artery in 7 patients, particularly in regard to the so-called shining-through effect through fiber bundles of the thinned nerve. Of all the patients, 88% reported at least improvement or cessation of their symptoms, including all of the patients with a shine-through effect. Conclusion ICG angiography could be a helpful adjunct in decompressing the trigeminal nerve and can guide the surgeon to the nerve-vessel conflict. Intensity of the fluorescence is powerful enough to shine through thinned and splayed trigeminal nerve fiber bundles.

Bilateral basal ganglia infarction following resection of a right parietal parasagittal dural tumour requiring sinus repair -- an atypical complication of an atypical venous drainage.

The case of a 68-year old woman who underwent surgery for a right parietal parasagittal dural tumour is reported. In the preoperative angiography the straight sinus failed to show. During tumour resection the lateral wall of the parietal superior sagittal sinus was opened and reconstructed. Postoperatively, the patient remained unresponsive. A computerized tomography scan revealed bilateral infarction of the basal ganglia. Angiography showed an occlusion of the superior sagittal sinus with hypervolaemia of the deep venous system. The patient did not recover. We conclude that patency of the superficial venous drainage system can be mandatory for drainage of the basal ganglia in cases with deep venous obstruction. To our knowledge, this is an extremely rare complication of neurosurgery in cortical supratentorial areas.

Outcome after microsurgery for meningiomas involving the internal auditory canal.

BACKGROUND: The subset of patients suffering from meningiomas truly originating in or extending into the internal auditory canal is not well described in the literature. OBJECTIVE: To evaluate postoperative facial motor and hearing outcomes in patients undergoing resection of meningiomas originating in or extending into the internal auditory canal. METHODS: Chart reviews were done of 19 consecutive patients undergoing surgery for meningiomas originating in or extending into the internal auditory canal at the Mayo Clinic, Rochester, with emphasis on clinical exam and audiometry. RESULTS: Median follow-up for the entire group was 29 months. Seventy-four percent of patients had stable facial nerve function. One patient experienced improvement. Postoperative cochlear nerve function was unchanged in 74% of patients and worsened in 21% of patients. One patient with a sudden preoperative hearing loss improved to full hearing at 3 months. CONCLUSION: Every attempt should be made to preserve hearing and facial motor function in surgical removal of posterior fossa meningiomas that originate in or extend into the internal auditory canal. Normal or nearly normal facial nerve function can be preserved in 88% of patients presenting with normal facial nerve function; serviceable hearing can be preserved in 92% of patients who present with normal hearing. A standard retrosigmoid craniotomy with drilling of the posterior canal wall of the internal auditory canal worked well in the majority of cases.

Spontaneous regression of vestibular schwannomas after resection of contralateral tumor in neurofibromatosis Type 2.

The authors report on 2 patients with bilateral vestibular schwannomas (VSs) who underwent unilateral surgical tumor removal. One patient was followed up for 4 years, the other for 9; in both cases, the contralateral VS regressed markedly without any additional treatment during the follow-up period. Serial MR imaging was performed to monitor the untreated tumor, which in both cases involved the only hearing ear. The tumors were assessed volumetrically. The contralateral tumors appeared to enlarge mildly at initial follow-up and then, with no treatment, regressed (to 23% of the original maximum volume in Case 1 and to 15% of the original maximum in Case 2). The largest posterior fossa diameter decreased from 30.1 mm to 18.6 mm in Case 1 over 4 years and from 27 mm to 16 mm over 8 years in Case 2. Hearing declined only mildly during follow-up in both patients. These cases demonstrate the first well-documented, long-term, spontaneous VS regressions in patients with neurofibromatosis Type 2. They underline the importance of careful observation of VS involving the only hearing ear in the management of bilateral VS to determine the natural growth pattern of the tumors. The mechanism of the dramatic spontaneous tumor regression is uncertain.

Intracavitary chemotherapy (paclitaxel/carboplatin liquid crystalline cubic phases) for recurrent glioblastoma -- clinical observations.

Human malignant brain tumors have a poor prognosis in spite of surgery and radiation therapy. Cubic phases consist of curved biocontinuous lipid bilayers, separating two congruent networks of water channels. Used as a host for cytotoxic drugs, the gel-like matrix can easily be applied to the walls of a surgical resection cavity. For human glioblastoma recurrences, the feasibility, safety, and short-term effects of a surgical intracavitary application of paclitaxel and carboplatin encapsulated by liquid crystalline cubic phases are examined in a pilot study. A total of 12 patients with a recurrence of a glioblastoma multiforme underwent re-resection and received an intracavitary application of paclitaxel and carboplatin cubic phases in different dosages. Six of the patients received more than 15 mg paclitaxel and suffered from moderate to severe brain edema, while the remaining patients received only a total of 15 mg paclitaxel. In the latter group, brain edema was markedly reduced and dealt medically. Intracavitary chemotherapy in recurrent glioblastoma using cubic phases is feasible and safe, yet the clinical benefit remains to be examined in a clinical phase II study.

Local chemotherapy of F98 rat glioblastoma with paclitaxel and carboplatin embedded in liquid crystalline cubic phases.

Implanted drug carrier systems for retarded chemotherapy against gliomas are mainly based upon polymers containing nitrosoureas. The authors have developed an intracavitary carrier system of biodegradable liquid crystalline cubic phases encapsulating carboplatin and paclitaxel and studied it for release kinetics, antitumor activity, and survival prolongation. A total of 61 Fisher rats with F98 tumors were divided into six treatment groups at day 12 post-inoculation, receiving either no treatment, surgery with partial tumor resection, or partial resection with implantation of cubic phases containing either paclitaxel and carboplatin, paclitaxel alone, carboplatin alone, or no drug. Animals were killed for tumor size analysis at day 21 post-inoculation (n=28) or were included in survival studies (n=33). Additional 12 animals received a paclitaxel/carboplatin application and were killed at different time intervals (6 h, 24 h, 48 h, 5 d, 7 d, 10 d post-agent application) for in vivo diffusion studies. Animals from the paclitaxel/carboplatin group showed a significantly smaller tumor (mean 3.25 mm2+/-SD 1.79 mm2) than animals from the control group (15.30+/-5.86 mm2; P=0.0031), animals having received the empty matrix (11.62+/-6.66 mm2; P=0.0241), and animals after tumor resection without implantation (20.87+/-3.56 mm2; P