Hans Christoph Ludwig

Piezoelectric bone surgery: a revolutionary technique for minimally invasive surgery in cranial base and spinal surgery? Technical note.

OBJECTIVE: Piezoelectric surgery represents an innovative, ultrasonic surgery technique for performing a safe and effective osteotomy or osteoplasty that contrasts with the traditional hard and soft tissue management methods with rotating instruments. METHODS: Because of its physical and mechanical properties, the definitive clinical advantage of piezoelectric bone surgery with regard to precision cutting lies in the sparing of vital neurovascular bundles or general soft tissue and better visualization of the surgical field, thus suggesting its great safety. Piezoelectric bone surgery has been previously described only in oral and maxillofacial operative procedures in adults. RESULTS: Five children between the age of 6 and 84 months were operated on for craniosynostosis, tethered cord, and an extraconal intraorbital tumor. The usefulness of piezoelectric bone surgery during neurosurgical procedures is presented for these cases. This technique is especially recommended when there are anatomic difficulties because of poor intraoperative visibility or the presence of delicate anatomic structures. CONCLUSION: The present preliminary report (comprising illustrative case reports) demonstrates and introduces for the first time the utility of piezoelectric bone surgery in cranial base and spinal surgery in children. Until now, there has been no documented neurosurgical experience of this technique even in adults.

The role of neuronavigation in intracranial endoscopic procedures

In occlusive hydrocephalus, cysts and some ventricular tumours, neuroendoscopy has replaced shunt operations and microsurgery. There is an ongoing discussion if neuronavigation should routinely accompany neuroendoscopy or if its use should be limited to selected cases. In this prospective clinical series, the role of neuronavigation during intracranial endoscopic procedures was investigated. In 126 consecutive endoscopic procedures (endoscopic third ventriculostomy, ETV, n = 65; tumour biopsy/resection, n = 36; non-tumourous cyst fenestration, n = 23; abscess aspiration and hematoma removal, n = 1 each), performed in 121 patients, neuronavigation was made available. After operation and videotape review, the surgeon had to categorize the role of neuronavigation: not beneficial; beneficial, but not essential; essential. Overall, neuronavigation was of value in more than 50% of the operations, but its value depended on the type of the procedure. Neuronavigation was beneficial, but not essential in 16 ETVs (24.6%), 19 tumour biopsies/resections (52.7%) and 14 cyst fenestrations (60.9%). Neuronavigation was essential in 1 ETV (2%), 11 tumour biopsies/resections (30.6%) and 8 cyst fenestrations (34.8%). Neuronavigation was not needed/not used in 48 ETVs (73.9%), 6 endoscopic tumour operations (16.7%) and 1 cyst fenestration (4.3%). For ETV, neuronavigation mostly is not required. In the majority of the remaining endoscopic procedures, however, neuronavigation is at least beneficial. This finding suggests integrating neuronavigation into the operative routine in endoscopic tumour operations and cyst fenestrations.

Neuropathy of the Sural Nerve Caused by External Pressure

The sural nerve is the most common nerve serving as a donor in nerve grafting procedures. Also, it is routinely biopsied for diagnostic purposes in cases of unusual neuropathies. Neurosurgeons are not frequently confronted with the syndrome of sural nerve neuropathy, except as a complication of sural nerve biopsy [2]. In our report a rare case of compressive sural nerve neuropathy is presented.

Elevated cerebral perfusion pressure and low colloid osmotic pressure as a risk factor for subdural space-occupying hygromas?

BACKGROUND Space-occupying subdural hygromas are a late complication of severe traumatic brain injury (TBI) and may delay the patients recovery. To evaluate the risk factors involved, we performed a semiretrospective, -prospective analysis of three groups of patients, which differed with regard to the techniques used in the management of their cerebral perfusion pressure (CPP) and colloid osmotic pressure (COP) to determine the occurrence of space-occupying subdural hygromas. PATIENTS AND METHODS Between 1989 and 1997 we examined 696 patients after a severe TBI: Group 1. 1989-1994 mean CPP: 67 (elevated for therapeutic reasons by catecholamines, if necessary), mean COP: 19. Group 2. January 1995-October 1996, mean CPP: 77, mean COP: 20. Group 3. November 1996-December 1997, mean CPP: 79, mean COP: 23 (elevated for therapeutic reasons by infusions of colloids). The groups were comparable for other criteria. RESULTS Compared to Group 1, Group 2, with a high CPP but lower COP, showed a significantly higher (p < 0.01; chi2-test with correction of Yates) percentage of posttraumatic subdural hygromas with space-occupying aspects, clinical signs of bradycardia, hypertension and impaired consciousness requiring surgery (Group 1: 1.75%; Group 2: 10.46%; Group 3: 0%). In Group 3 we saw no patient with a space-occupying hygroma. CONCLUSION We conclude that iatrogenic elevated CPP, which has been reported to be helpful in preventing secondary ischemic damage after a severe TBI, may be harmful to a patient if the COP is not maintained within physiological ranges.

PROSAIKA: A prospective multicenter registry with the first programmable gravitational device for hydrocephalus shunting

OBJECTIVE Cerebrospinal fluid (CSF) overdrainage is a major problem in shunt therapy for hydrocephalus. The adjustable gravitational valve proSA allows for the first time a targeted compensation for overdrainage in the upright position without interfering with the differential pressure valve. To evaluate benefit, safety and reliability, the multicenter prospective registry PROSAIKA was conducted in 10 German neurosurgical centers. METHODS Between March 2009 and July 2010, 120 hydrocephalic patients undergoing first time shunt implantation or shunt revision using proSA entered the study. 93 patients completed the 12 months follow-up. RESULTS Hydrocephalus symptoms were improved in 86%, unchanged in 9% and deteriorated in 3%. In 51%, the proSA opening pressure was readjusted one or several times to treat suspected suboptimal shunt function, this resulted in clinical improvement in 55%, no change in 25%, and deterioration in 20% of these patients. The 1 year censored proSA shunt survival rate was 89%. Device related shunt failure was seen in two cases. CONCLUSIONS This is the first clinical report on the implantation of the adjustable gravitational valve proSA with a follow-up of 12 months in a substantial number of patients. Irrespective of different hydrocephalus etiologies and indications for shunt surgery, the overall results after 12 months were very satisfying. The high frequency of valve readjustments underlines the fact that preoperative selection of the appropriate valve opening pressure is difficult. The low number of revisions and complications compared to other valves proves that proSA implantation adds no further risk; this valve is reliable, helpful and safe.

Bedside measurement of the third ventricle's diameter during episodes of arising intracranial pressure after head trauma : using transcranial real-time sonography for a non-invasive examination of intracranial compensation mechanisms

SummaryUsing transcranial real-time sonography, changes in the axial diameter of the third ventricle during manoeuvres, which increased intracranial pressure (ICP), were measured in 28 patients with moderate to severe head injury. The measurements were correlated with ICP measured by epidural pressure monitoring. We observed reductions in diameter ranging from 0.3 to 1.1 mm with rises in intracranial pressure of at least 5 mm in 22 patients of whom only one died. In 6 additional patients, no changes in diameter were seen, and 5 of the 6 died. We interprete that poor outcome as a measurable inability for the brain to expel cerebrospinal fluid into extracerebral compartments during increased ICP. Transcranial real-time sonography may provide additional information about intracranial cerebral fluid dynamics and compliance.

Unusual localization of a choroid plexus papilloma in a 4-year-old female

Choroid plexus papillomas are rare tumors that are confined to areas in which the choroid plexus is normally located. In children, choroid plexus papillomas are predominantly located in the lateral ventricles. Clinically they present with signs of raised intracranial pressure, such as vomiting and increasing head size. Here we report on the clinical, radiologic, and histologic findings of a 4-year-old female who was found to have a tumor in the posterior fossa that had all the histologic hallmarks of a choroid plexus papilloma. This tumor did not originate from the roof of the fourth ventricle as expected but from the ependymal lining covering the median rostral medulla near the pontomedullary junction, a location that so far has not been reported.

Early surgical management and long-term surgical outcome for intraventricular hemorrhage–related posthemorrhagic hydrocephalus in shunt-treated premature infants

OBJECTIVE Perinatal intraventricular hemorrhage (IVH) in premature neonates may lead to severe neurological disability and lifelong treatment requirement for consecutive posthemorrhagic hydrocephalus (PHHC). Early CSF diversion as a temporizing measure, or a permanent ventriculoperitoneal shunt (VPS), is the treatment of choice. Preterm neonates are not only at high risk for different perinatal but also for treatment-related complications. The authors reviewed their institutional neurosurgical management for preterm neonates with IVH-related PHHC and evaluated shunt-related surgical outcome for this particular hydrocephalus etiology after completion of a defined follow-up period of 5 years after initial shunt insertion. METHODS The authors retrospectively analyzed early surgical management for preterm newborns who presented with IVH and PHHC between 1995 and 2015. According to the guidelines, patients received implantation of a ventricular access device (VAD) for temporizing measures or direct VPS insertion as first-line surgical treatment. Surgical outcome was evaluated for a subgroup of 72 patients regarding time to first shunt revision and the mean number of shunt revisions during a time span of 5 years after initial shunt insertion. Gestational age (GA), extent of IVH, and timing and modality of initial surgical intervention were analyzed for potential impact on corresponding surgical outcome. RESULTS A total cohort of 99 preterm newborns with GAs ranging from 22 to 36 weeks (mean 28.3 weeks) with perinatal IVH-related PHHC and a median follow-up duration of 9.9 years postpartum could be selected for further investigation. Extent of perinatal IVH was defined as grade III or as periventricular hemorrhagic infarction in 75% of the patient cohort. Seventy-six patients (77%) underwent VAD insertion and temporizing measures as initial surgical treatment; for 72 (95%) of these a later conversion to permanent ventriculoperitoneal shunting was performed, and 23 patients received direct VPS insertion. Etiological and treatment-related variables revealed no significant impact on revision-free shunt survival but increased the mean numbers of shunt revisions after 5 years for low GA, higher-order IVH in the long term. CONCLUSIONS Low GA and higher-order IVH in preterm neonates with PHHC who are treated with VPSs show no significant impact on time to first shunt revision (i.e., revision-free shunt survival), but marked differences in mean revision rates evaluated after completion of 5 years of follow-up. Temporizing measures via a VAD represent a rational strategy to gain time and decision guidance in preterm patients with PHHC before permanent VPS insertion.

Endoscopic cystoventriculostomy and ventriculo-cysternostomy using a 2.0 micron fiber guided cw laser in children with hydrocephalus

Preterm infants have a high incidence of post hemorrhagic or post infectious hydrocephalus often associated with ventricular or arachnoic cysts which carry a high risk of entrapment of cerebrospinal fluid (CSF). In these cases fenestration and opening of windows within the separating membranes are neurosurgical options. In occlusive hydrocephalus caused by aquaeductal stenosis 3rd ventriculostomy is the primary choice of the operative procedures. Although Nd:YAG and diode lasers have already been used in neuroendoscopic procedures, neurosurgeons avoid the use of high energy lasers in proximity to vital structures because of potential side effects. We have used a recently developed diode pumped solid state (DPSS) laser emitting light at a wavelength of 2.0 micron (Revolix TM LISA laser products, Katlenburg, Germany), which can be delivered through silica fibres towards endoscopic targets. From July 2002 until May 2005 22 endoscopic procedures in 20 consecutive patients (age 3 months to 12 years old) were performed. Most children suffered from complex post hemorrhagic and post infectious hydrocephalus, in whom ventriculoperitoneal shunt devices failed to restore a CSF equilibrium due to entrapment of CSF pathways by the cysts. We used two different endoscopes, a 6 mm Neuroendoscope (Braun Aesculap, Melsungen, Germany) and a 4 mm miniature Neuroscope (Storz, Tuttlingen, Germany). The endoscopes were connected to a standard camera and TV monitor, the laser energy was introduced through a 365 micron core diameter bare ended silica fibre (PercuFib, LISA laser products, Katlenburg, Germany) through the endoscopes working channel. The continuous wave laser was operated at power levels from 5 to 15 Watt in continuous and chopped mode. The frequency of the laser in chopped mode was varied between 5 and 20 Hz. All patients tolerated the procedure well. No immediate or long term side effects were noted. In 3 patients with cystic compression of the 4th ventricle, insertion of a shunt device could be avoided. All 3rd ventriculostomies were sufficient for therapy of hydrocephalus, postoperatively MRI scans showed a bright flow void signal. The authors conclude that the use of the new Revolix laser enables safe and effective procedures in neuroendoscopy.

Endoscopic cystoventriculostomy and ventriculocysternostomy using a recently developed 2.0-micron fiber-guided high-power diode-pumped solid state laser in children with hydrocephalus

Preterm infants have a high incidence of post hemorrhagic or post infectious hydrocephalus often associated with ventricular or arachnoic cysts which carry a high risk of entrapment of cerebrospinal fluid (CSF). In these cases fenestration and opening of windows within the separating membranes are neurosurgical options. Although Nd:YAG- and diode-lasers have already been used in neuroendoscopic procedures, neurosurgeons avoid the use of high energy lasers in proximity to vital structures because of potential side effects. We have used a recently developed diode pumped solid state (DPSS) laser emitting light at a wavelength of 2.0 μm (Revolix TM LISA laser products, Katlenburg, Germany), which can be delivered through silica fibres towards endoscopic targets. From July 2002 until June 2004 fourteen endoscopic procedures in 12 consecutive patients (age 3 months to 12 years old) were performed. Most children suffered from complex post hemorrhagic and post infectious hydrocephalus, in whom ventriculoperitoneal shunt devices failed to restore a CSF equilibrium due to entrapment of CSF pathways by the cysts. We used two different endoscopes, a 6 mm Neuroendoscope (Braun Aesculap, Melsungen, Germany) and a 4 mm miniature Neuroscope (Storz, Tuttlingen, Germany). The endoscopes were connected to a standard camera and TV monitor, the laser energy was introduced through a 365 μm core diameter bare ended silica fibre (PercuFib, LISA laser products, Katlenburg, Germany) through the endoscope’s working channel. The continuous wave laser was operated at power levels from 5 to 15 Watt in continuous and chopped mode. The frequency of the laser in chopped mode was varied between 5 and 20 Hz. All patients tolerated the procedure well. No immediate or long term side effects were noted. In 3 patients with cystic compression of the 4th ventricle, insertion of a shunt device could be avoided. The authors conclude that the use of the new RevolixTM laser enables safe and effective procedures in neuroendoscopy.