Near-infrared indocyanine green videoangiography versus microvascular Doppler sonography in aneurysm surgery.

INTRODUCTION: The quality of surgical treatment of intracranial aneurysms is determined by complete aneurysm occlusion and restoration of flow in the parent, branching and perforating vessels. In postoperative digital subtraction angiography (DSA), unexpected aneurysm residuals and vessel occlusions are frequently detected. Here, the value of two nearly noninvasive and cost-effective techniques for intraoperative flow evaluation (near-infrared indocyanine green video angiography (ICG-VA) and microvascular Doppler sonography (mDs)) is investigated in a prospective study. PATIENTS AND METHODS: Over a period of 10 months, the authors surgically clipped 50 aneurysms under intraoperative pre- and post-clipping evaluation of flow in the parent, branching and perforating vessels and the aneurysm sack by the two techniques. Intraoperative applicability of each technique was compared to each other and to postoperative digital subtraction angiography as standard evaluation technique. RESULTS: Forty-five aneurysms were totally occluded without vessel compromise (90%). Intraoperatively, ICG-VA was considered useful in 43 cases (86%) and mDs in 44 cases (88%), respectively. Both techniques could compensate each other's weak points to a certain degree; but two branch occlusions (4%) and three neck remnants (6%) were revealed by postoperative DSA. CONCLUSION: Both techniques have specific drawbacks that could be compensated by each other, to a certain extent. Intraoperatively, ICG-VA and mDs should not be considered competitive, but complementary. This study implicates that the combination of both applications on a routine basis assures the quality of aneurysm surgery by nearly noninvasive and cost-effective techniques. However, DSA remains the gold standard for evaluation of aneurysm occlusion.

Endoscopic diagnosis and treatment of far distal obstructive hydrocephalus.

PURPOSE: Obstruction of the CSF circulation distal to the fourth ventricle is a rare cause of noncommunicating hydrocephalus. Endoscopic third ventriculostomy (ETV) represents one of the treatment options, but reports of results are rare. METHODS: Between March 1997 and June 2008, 20 ETVs in 20 patients (mean 32.4 years, range 1 month-79 years) for noncommunicating hydrocephalus distal to the fourth ventricle were undertaken. All patients suffered from severe internal hydrocephalus and typical clinical symptoms. In addition to the standard ETV, a transaqueductal inspection of the posterior fossa with a flexible scope was performed. All patients were prospectively followed. RESULTS: An ETV was achieved in all patients. It was clinically successful in 15 of 20 patients (75%) with an improvement of 50% (three out of six) of the pediatric and of 83% (12 out of 14) of the adult population. A reduction of ventricle size was found in ten (50%). Five patients (25%) received ventriculoperitoneal shunting. A transaqueductal inspection of the posterior fossa cerebrospinal fluid (CSF) pathways was performed in 16. In the remaining four patients, no inspection with the flexible scope was done. One clinically silent fornix contusion and one CSF fistula which was treated conservatively occurred. There was no permanent morbidity. CONCLUSIONS: ETV is a successful treatment option in CSF pathway obstructions distal to the fourth ventricle. Although the success rate particularly of the pediatric population appears to be lower than with other indications of obstructive hydrocephalus, a relevant part of the patient population improves after ventriculostomy and shunting can be avoided.

Endoscopic third ventriculostomy in obstructive hydrocephalus due to giant basilar artery aneurysm.

OBSTRUCTIVE: hydrocephalus due to giant basilar artery (BA) aneurysm is a rare finding, and endoscopic treatment has not been reported. Here the authors present their experience with endoscopic third ventriculostomy (ETV) in obstructive hydrocephalus due to giant BA aneurysm. Between December 2000 and March 2007, 3 patients (2 men and 1 woman; age range 32-80 years) underwent an ETV for the treatment of obstructive hydrocephalus caused by a giant BA aneurysm. All 3 patients presented with cephalgia, nausea, vomiting, and a variable decrease in consciousness. An obstructive hydrocephalus caused by a giant BA aneurysm was found in each case as the underlying pathological entity. Intraoperatively, a narrowing of the third ventricle by upward displacement of the tegmentum was found in all 3 patients. A standard ETV was performed and included an inspection of the prepontine cisterns. The endoscopic treatment was successful in all patients with respect to clinical signs and radiological ventricular enlargement. No complications were observed. In all, the endoscopic ventriculostomy was proven to be a successful treatment option in obstructive hydrocephalus even if it is caused by untreated giant BA aneurysm.

Endoscopic cystoventriculostomy for treatment of paraxial arachnoid cysts.

OBJECT: The optimal therapy of arachnoid cysts is controversial. In symptomatic extraventricular arachnoid cysts, fenestration into the basal cisterns is the gold standard. If this is not feasible, shunt placement is frequently performed although another endoscopic option is available. METHODS: Between March 1997 and June 2006, 12 endoscopic cystoventriculostomies were performed for the treatment of arachnoid cysts in 11 patients (4 male and 7 female patients, mean age 52 years [range 14-71 years]). All patients were prospectively followed up. RESULTS: In 11 cases, the arachnoid cysts were frontotemporoparietal and fenestration was performed into the lateral ventricle. In 1 case, the arachnoid cyst was located in the cerebellum and the cyst was fenestrated into the fourth ventricle. Neuronavigational guidance was used in all but 1 case. Endoscopic cystoventriculostomy was performed in all cases without complications. No stents were placed. The mean surgical time was 71 minutes (range 30-110 minutes). The mean follow-up period was 42.7 months (range 19-96 months) per surgical case and 48.8 months (range 19-127 months) per patient. Symptoms improved after 11 of the 12 procedures; 7 of the 11 patients became symptom-free and the others had only mild residual symptoms. The patient who did not experience clinical improvement suffered from depression and demonstrated a significant decrease of the cyst size on the postoperative MR imaging. After 11 of 12 procedures, a decrease in cyst size was observed. In 1 case, a subdural hematoma developed; it required surgical treatment 3 months after surgery. In another case, reclosure of the stoma required repeated endoscopic cystoventriculostomy more than 7 years after the initial procedure. CONCLUSIONS: Overall, endoscopic cystoventriculostomy represents a useful treatment option for patients with paraxial arachnoid cysts in whom a standard cystocisternotomy is not feasible. Based on the results in this case series, stent placement appears not to be required. Despite the long mean follow-up of almost 4 years, however, a longer follow-up period seems to be required before definite conclusions can be drawn.

German neuroendoscopy above the skull base.

Endoscopy plays an important part in current minimally invasive neurosurgery. The concepts, indications, and standards of current neuroendoscopy were developed in the beginning of the 1990s by several groups of neurosurgeons. Several factors contributed to its success and acceptance, including technical development, influence of other disciplines, and adaptation to neurosurgical requirements. This historical survey focuses on the period when this technique initially emerged, including the scientific discussions of each group as well as the arguments and reasons that led to present intraventricular neuroendoscopy. Interestingly, despite the almost independent development of neuroendoscopic systems and techniques, the available systems and techniques applied these days grossly correspond. Rigid rod-lens endoscopes are generally accepted as the best option among the various available instrument sets. Nevertheless, frameless as well as frame-based stereotactic endoscopy and flexible steerable endoscopes might have their applications as well.

PEEK cage cervical ventral fusion in spondylodiscitis.

PURPOSE: Cervical spondylodiscitis is a quite rare finding regarding the number and the common location of spinal abscesses in the lumbar region. While in thoracic and lumbar discitis, single-step surgery with neural decompression, disc space evacuation, and subsequent fusion is well known, there is no such report in cervical discitis. Here the authors present their experience with ventral polyetherketone (PEEK) cage fusion in cervical spondylodiscitis in a single-step procedure. METHODS: Between January 2006 and November 2008, five patients (three men, two woman; ages 71, 77, 58, 66 and 66 years) suffering from cervical spondylodiscitis and epidural abscess underwent disc evacuation, myelon decompression and subsequent ventral fusion using an empty PEEK cage disc replacement in one single setting. All five patients presented with significant neurological symptoms like cervicobrachialgia, tetraparesis and disturbance of the urinary incontinence. In all five patients, disc evacuation, myelon decompression and cervical fusion using a PEEK cage disc replacement in a single-stage surgery were performed. All wounds were closed primarily. Postoperatively, all patients received a specific antibiotic therapy for at least 6 weeks. RESULTS: This treatment strategy was successful in all patients with respect to clinical signs, laboratory parameters and radiological findings. All patients improved neurologically. Follow-up revealed a stable osteosynthesis without signs of instability. One cage was explanted despite neurological improvement and normal infectious parameters at another surgical department. No complications were observed. CONCLUSIONS: In all, abscess drainage and ventral fusion with PEEK-cage disc replacement in one single setting was proven to be a successful treatment option in cervical discitis and spinal epidural abscess.

A new endoscopic spine system: the first results with "Easy GO".

PURPOSE: Endoscopy meets increasing interest by spine surgeons. However, endoscopic results are diverging and many spinal endoscopic systems are difficult to apply and handle. METHODS: A system for endoscopic spinal surgery was developed where the main goals were: (1) easy intraoperative handling with standard microsurgical techniques, and (2) avoidance of a prolonged learning curve. The system consists of various dilators, two different work sheaths, two different 30 degrees endoscopes, and an endoscope holder. RESULTS: Between August 2006 and April 2008, 80 spinal surgeries were performed in degenerative lumbar spine cases (mean age 52 years, range 22-85 years). Intraoperatively, the system was easy to handle. Standard microsurgical techniques were used. Mean surgical time scored 75 min (range 28-168 min). There was no intraoperative complication, no new postoperative deficit and no infection. In four cases, the endoscope was abandoned and the procedure microsurgically continued (5%). At the last follow-up (mean FU 10 months, range 2 weeks up to 21 months), 89% of the patient were pain free (71/80). Four patients suffered from recurrent disc prolapses (5%). Another five patients (6%) were not satisfied without evidence of re-prolaps. Of those who answered the questionnaire of patient satisfaction, 83% (45/54) considered their postoperative status as excellent, 13% as good (7/54), 4% were not satisfied (2/54). CONCLUSIONS: The Easy GO system was easy and safe to handle with the standard bimanual microsurgical technique and good postoperative results. Further studies are needed to show a significant advantage of the technique in comparison to the microsurgical standard procedure.

Chronic subdural hematoma--craniotomy versus burr hole trepanation.

The authors present a series of more than 200 surgical procedures for chronic subdural hematoma in a 5-year-period. Clinical presentation and neurosurgical treatment were regarded with a special focus on the surgical technique. Between March 2003 and July 2008, 193 patients (113 male and 80 female, mean age 72.5 yrs [range 26-97 yrs]) suffering from chronic subdural hematoma were retrospectively analyzed. One-hundred-fifty-one craniotomies and 42 burr holes were performed. Forty-two craniotomy patients (27.8%) in contrast to 6 burr hole patients (14.3%) required surgical revision. A craniectomy was performed as an ultima ratio after at least 2 prior evacuations in 3 cases. Chronic subdural hematoma is a disease of the elderly. A craniotomy seems to possess a higher rate of recurrence of the chronic subdural hematoma so that a burr hole evacuation should be preferred. Craniectomy might be a good therapeutic option in complicated recurrent chronic subdural hematomas.

Effect of granulocyte colony-stimulating factor on the cochlear nuclei after creation of a partial nerve lesion: an experimental study in rats.

OBJECTIVE The risk of injury of the cochlear nerve during angle (CPA) surgery is high. Granulocyte colony-stimulating factor (G-CSF) has been found in various experimental models of peripheral and CNS injury to have a neuroprotective effect by inhibiting apoptosis and inflammation. However, to the authors' knowledge, the influence of G-CSF on cochlear nerve regeneration has not been reported. This study investigated the neuroprotective effect of G-CSF after a partial cochlear nerve lesion in rats. METHODS A lesion of the right cochlear nerve in adult male Sprague-Dawley rats was created using a water-jet dissector with a pressure of 8 bar. In the first group (G-CSF-post), G-CSF was administrated on Days 1, 3, and 5 after the surgery. The second group (G-CSF-pre/post) was treated with G-CSF 1 day before and 1, 3, and 5 days after applying the nerve injury. The control group received sodium chloride after nerve injury at the various time points. Brainstem auditory evoked potentials (BAEPs) were measured directly before and after nerve injury and on Days 1 and 7 to evaluate the acoustic function of the cochlear nerve. The animals were sacrificed 1 week after the operation, and their brains were fixed in formalin. Nissl staining of the cochlear nuclei was performed, and histological sections were analyzed with a light microscope and an image-processing program. The numbers of neurons in the cochlear nuclei were assessed. RESULTS The values for Waves 2 and 4 of the BAEPs decreased abruptly in all 3 groups in the direct postoperative measurement. Although the amplitude in the control group did not recover, it increased in both treatment groups. According to 2-way ANOVA, groups treated with G-CSF had a significant increase in BAEP Wave II amplitudes on the right side (p = 0.0401) after the applied cochlear nerve injury. With respect to Wave IV, a trend toward better recovery in the G-CSF groups was found, but this difference did not reach statistical significance. In the histological analysis, higher numbers of neurons were found in the G-CSF groups. In the statistical analysis, the difference in the numbers of neurons between the control and G-CSF-post groups reached significance (p = 0.0086). The difference in the numbers of neurons between the control and G-CSF-pre/post groups and between the G-CSF-post and G-CSF-pre/post groups did not reach statistical significance. CONCLUSIONS The use of G-CSF improved the function of the eighth cranial nerve and protected cochlear nucleus cells from destruction after a controlled partial injury of the nerve. These findings might be relevant for surgery that involves CPA tumors. The use of G-CSF in patients with a lesion in the CPA might improve postoperative outcomes.

Influence of Prior Cervical Surgery on Surgical Outcome of Endoscopic Posterior Cervical Foraminotomy for Osseous Foraminal Stenosis.

BACKGROUND: Posterior cervical foraminotomy is a valuable option as a treatment for cervical radiculopathy caused by osseous foraminal stenosis. Here the authors present their technique and results in a series of patients with and without previous surgery. METHODS: Forty-five patients suffering from cervical osseous foraminal stenosis were operated on via a microendoscopic posterior approach with the EasyGO system. All procedures were video recorded and afterwards retrospectively analyzed. The primary evaluation criterion was prior surgery or no prior surgery. Additionally, postoperative outcome according to Odom's criteria and Neck Disability Index (NDI), reoperation rate, and complications was considered. RESULTS: The 45 patients of this study showed an overall clinical success rate of 84%. There was no emergency stopping of any endoscopic procedure. Twenty patients (44.4%) had no and 25 patients (55.6%) had previous cervical surgery. In patients without previous surgery, the clinical success rate was 95.2%; NDI was 12%; and 100% of patients reported reduction of their preoperative arm pain and motor recovery. In patients with previous surgery, the clinical success rate was 75%. NDI was 24%. Most patients (91.7%) reported reduction of their preoperative arm pain, and 66.7% reported recovery of motor strength. CONCLUSION: This retrospective analysis shows that microendoscopic posterior cervical foraminotomy is a successful option in the treatment of osseous cervical foraminal stenosis. Nevertheless, clinical success in patients with previous surgery is much lower compared with patients without previous surgery. Thus, a more thorough clinical workup is recommended to identify the patients who are not going to benefit before subsequent surgical procedures.

Endoscopic Posterior Cervical Foraminotomy as a Treatment for Osseous Foraminal Stenosis.

BACKGROUND: Posterior cervical foraminotomy is a valuable treatment option for cervical radiculopathy. Here the authors present their technique and results in the treatment of a series of patients suffering from osseous foraminal stenosis. METHODS: Forty-three patients suffering from cervical osseous foraminal stenosis were operated on via a posterior approach with the EasyGO endoscopic system. Decompression was performed in 1 segment in 31 patients, in 2 segments in 11 patients, and in 3 segments in 1 patient. Bilateral decompression was performed in 4 cases. Twenty-four (55.8%) patients had been subjected to previous spine surgery. All procedures were video recorded and afterwards retrospectively analyzed. In addition, particular reference was given to previous cervical spine surgery, postoperative outcome, reoperation rate, and complications. RESULTS: The endoscopic system was easy to handle intraoperatively in all procedures. No emergency stopping was required. Forty-one patients reported improved and/or even no remaining pain postoperatively (95%). Thirty-five patients (81.4%) regained full motor strength. Clinical success rate with respect to Odom's criteria reached 39 patients (90.7%). One reoperation was needed due to postoperative hematoma (2.3%). One patient suffered from transient worsening of his preoperative paresis (2.3%). Neither dural tear nor nerve root injury was observed. Reoperation rate due to degenerative changes was 18.6% (8 of 43 patients). CONCLUSIONS: This retrospective analysis shows that posterior endoscopic decompression is a successful option in the treatment of osseous cervical foraminal stenosis.

Endoscopic third ventriculostomy: preoperative considerations and intraoperative strategy based on 300 procedures.

PURPOSE: Although successful endoscopic third ventriculostomy (ETV) has been reported for many indications, peculiarities of the surgical technique in each separate indication require particular respect. METHODS: A detailed account of the authors' surgical technique, their presurgical considerations, and their intraoperative strategies to perform ETV is presented. Surgery of representative obstructive hydrocephalus cases in posterior fossa lesions (cerebellar infarction, posterior fossa tumor), in distortion of the ventricular system (intracranial hemorrhage, basilar artery aneurysm) and in membranous obstruction (aqueductal stenosis, posterior fossa malformation), is illustrated in detail. RESULTS: In posterior fossa lesions, careful evaluation of the prepontine space and localization of the basilar artery is mandatory. Recognition of mammillary bodies and infundibular recess is of particular importance since the third ventricle floor is rather thick and nontranslucent. In distortion of the ventricular system, careful analysis of the preoperative imaging allows the selection of the optimal approach. Sometimes, blood clot removal and vigorous irrigation is required. Frequently, the landmarks are difficult to identify. These are cases for experienced endoscopic neurosurgeons. In aqueductal stenosis and posterior fossa malformation, perforation of the often thin and translucent ventricular floor is easy because of clear anatomical landmarks. Those are ideal candidates for ETV. For experienced neuroendoscopists, the authors advocate inspection of the fourth ventricle with a flexible scope to ensure cerebrospinal fluid (CSF) circulation obstruction. CONCLUSIONS: ETV is a frequent and well-established endoscopic technique. Based on the underlying pathology, the technique has to be modified to obtain good results with minimal complications.

Waterjet dissection in pediatric cranioplasty.

OBJECT: Waterjet dissection has been shown to separate tissues of different resistance, with preservation of blood vessels. In cranioplasty, separation of subcutaneous tissue and dura mater is often difficult to achieve because the various tissue layers strongly adhere to each other after decompressive craniotomy. In the present study, the potential advantages and drawbacks of the waterjet technique in cranioplasty after craniectomy and duraplasty are addressed. METHODS: The waterjet effect on fresh human cadaveric dura mater specimens as well as on several dural repair patches was tested in vitro under standardized conditions, with waterjet pressures up to 80 bar. Subsequently, 8 pediatric patients (5 boys, 3 girls; mean age 9.9 years, range 1.2-16.7 years) who had been subjected to decompressive craniectomy (7 with duraplasty including bovine pericardium as a dural substitute, 1 without duraplasty in congenital craniosynostosis) underwent waterjet cranioplasty. The waterjet was used to separate the galea and the dura mater. The technique was applied tangentially between the dura and the galea, with different pressure levels up to 50 bar. RESULTS: In vitro, fresh cadaveric human dura mater as well as 2 different dural repair substitutes showed a very high resistance to waterjet dissection up to 80 bar. The human dura and the various substitutes were dissected only after long-lasting exposure to the waterjet. Human dura was perforated at pressures of 60 bar and higher. Bovine pericardium dural substitute was perforated at pressures of 55 bar and higher. Artificial nonabsorbable polyesterurethane dural substitute was dissected at pressures of 60 bar and higher. In the clinical setting, the waterjet was able to separate galea and dura with minimal bleeding. No blood transfusion was required. Dissection of scarred tissue was possible by a waterjet of 40 bar pressure. Tissue layers were stretched and separated by the waterjet dissection, and a very reliable hemostasis resulted. This resulted in an effective reduction of bleeding, with < 60 ml blood loss in 7 of the 8 cases. Neither a dural tear nor a perforation of any duraplasty occurred during operative preparation. There were no operative or postoperative complications. CONCLUSIONS: The experimental and clinical data show that waterjet separation of dura mater, dural substitute, and galea can be performed with a high level of safety to avoid dural tears. The waterjet dissection stretches tissue layers, which results in a reliable hemostasis effect. This potentially results in an effective reduction of surgical blood loss, which should be the focus of further studies.