Stand-Alone Percutaneous Pedicle Screw Lumbar Fixation to Indirectly Decompress the Neural Elements in Spinal Stenosis: A Radiographic Assessment Case Series

BACKGROUND

 The ideal surgical treatment of lumbar canal stenosis remains controversial. Although decompressive open surgery has been widely used with good clinical outcome, minimally invasive indirect decompression techniques have been developed to avoid the complications associated with open approaches. The purpose of this study was to evaluate the radiologic outcome and safety of the indirect decompression achieved with stand-alone percutaneous pedicle screw fixation in the surgical treatment of lumbar degenerative pathologies.

METHODS

 Twenty-eight patients presenting with spinal degenerative diseases including concomitant central and/or lateral stenosis were treated with stand-alone percutaneous pedicle screw fixation. Radiographic measurements were made on axial and sagittal magnetic resonance (MR) images, performed before surgery and after a mean follow-up period of 25.2 months. Measurements included spinal canal and foraminal areas, and anteroposterior canal diameter.

RESULTS

 Percutaneous screw fixation was performed in 35 spinal levels. Measurements on the follow-up MR images showed statistically significant increase in the cross-sectional area of the spinal canal and the neural foramen, from a mean of 88.22 and 61.05 mm2 preoperatively to 141.52 and 92.18 mm2 at final follow-up, respectively. The sagittal central canal diameter increased from a mean of 4.9 to 9.1 mm at final follow-up. Visual analog scale (VAS) pain score and Oswestry Disability Index (ODI) both improved significantly after surgery (p < 0.0001).

CONCLUSION

 Stand-alone percutaneous pedicle screw fixation is a safe and effective technique for indirect decompression of the spinal canal and neural foramina in lumbar degenerative diseases. This minimally invasive technique may provide the necessary decompression in cases of common degenerative lumbar disorders with ligamentous stenosis.

Prognostic scoring system for surgical treatment of intramedullary spinal cord metastases

Although rare, intramedullary spinal cord metastases (ISCMs) are on the rise, most likely due to prolonged survival and improved outcomes as a result of the advances in cancer treatment for cancer patients. While the management of these lesions remains controversial, surgery for ISCM has recently been advocated for selected patients. We performed a retrospective analysis on 30 patients who were surgically treated for intramedullary spinal cord metastases in order to determine a preoperative prognostic scoring system to guide patient selection for surgical interventions. The scoring system was designed to decide between surgery or other therapeutic procedures. The five parameters selected and employed in the assessment system were: 1) patient's general condition, 2) age, 3) primary site of the cancer, 4) number of other extramedullary metastases and 5) severity of neurologic symptoms. Prognosis could not be predicted from a single parameter. These five factors were added together to give a prognostic score between 1 and 10. The average survival period of patients with a prognostic score between 1 and 3 points was 3 months; 11 patients with a score of 4 and 5 points had a mean survival of 7.63 months, while patients with a prognostic score between 6 and 10 was 14.8 months. According to our prognostic scoring system for surgical treatment of ISCM, surgery should be performed in those patients who score above 6 points, while radiotherapy/chemotherapy or palliative care is recommended for those who score between 1 and 3 points. A prognostic score of 4 and 5 represents a grey area where surgeons must use their judgment on whether to intervene either medically or surgically. This scoring system could facilitate decision-making in the management of patients with intramedullary spinal cord metastases.

Use of tissue sealant patch (TachoSil) in the management of cerebrospinal fluid leaks after anterior cervical spine discectomy and fusion

PURPOSE

The purpose of this study was to evaluate a fast, sutureless technique to repair anterior cervical dural tears. Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure for the treatment of cervical degenerative diseases. Although uncommon, incidental durotomy with cerebrospinal fluid (CSF) leak during ACDF is a potentially serious complication. Yet, its technical management for the prevention of CSF leak is controversial.

METHODS

Between September 2012 and June 2018 we encountered seven cases (2 female/5 male) presenting with intraoperative CSF leaks secondary to incidental dural tears during ACDF surgery. All the cases were surgically treated using a topical fibrin sealant patch (TachoSil) with high adesive strength and fibrin glue (Tisseel). Intraoperative source of leakage, time to leakage control, quantity of Sealant Sponge used and postoperative complications were evaluated.

RESULTS

Dural tears were tipically the result of dissection of adherent posterior longitudinal ligament and/or calcified disc from the cervical dural sac to allow full decompression of the spinal cord. Effective repair of dural tear defined as cessation of CSF leak after topical sealant agents application was achieved no later than one minute in all cases. Evident clinical and/or radiological postoperative CSF leak was used to determine the patient's postoperative result. Postoperative CSF leak was not evident during a minimum 6 months follow up.

CONCLUSIONS

In the present study, we have reported our experience with a new sealing technique to manage CSF leaks from iatrogenic cervical dural lacerations. Tachosil tissue sealant patch is a rapid sutureless technique that may help in repairing introperatively incidental dural tears, thus reducing the risk of postoperative CSF leaks. To our knowledge, this is the first series to report the use of Tachosil adhesive sealant patch for the treatment of incidental dural tears during anterior cervical discectomy.

Ultrasound-Guided percutaneous laser disc decompression (PLDD) with fluoroscopic validation for the treatment of cervical disc herniation: Technical note

OBJECTIVE

Percutaneous laser disc decompression (PLDD) has been regarded as an effective alternative for the treatment of cervical soft disc herniations. Repeated X-Ray scanning is essential when performing this technique.

DESIGN

Technical note.

METHODS

We present a new method for the treatment of cervical disc herniation using ultrasound to guide the needle entry to the cervical disc, to avoid excess of radiation exposure during the surgical procedure. We evaluated the efficacy of this cervical approach.We retrospectively reviewed the clinical data of 14 cases who underwent a PLDD under ultrasound (US) guidance for the treatment of contained cervical disc herniation using a 1470 Nm diode laser. The lower cervical discs (C5-C6 and C6-C7) were the most affected sites, accounting for 78.6% of surgical discs.A significant NRS reduction between baseline and 1 month (p = 0.0002) and between baseline and 12 months (p = 0.0007) was observed.

CONCLUSIONS

Our results support the conclusion that US guided PLDD with fluoroscopic validation is a minimally invasive technique for patients affected by herniated cervical discs, but proper choice of patients is critical. This approach should not be performed except after adequate training under close supervision of surgeons experienced in this procedure and in interventional US.

Percutaneous Laser Disc Decompression (PLDD) for the Treatment of Contained Lumbar Disc Herniation

Lumbar disc herniation is a common cause of back and radicular leg pain. A bulging annulus and contained herniated disc can compress a nearby exiting root as it enters the neuroforamen and may cause pain and neurological symptoms. Percutaneous laser disc decompression (PLDD) has been regarded as an effective alternative to microdiscectomy for the treatment of contained lumbar disc herniations. However, there is no consensus regarding the type of laser to use, the ideal wavelength, or the energy applied. The ideal laser irradiation should have a high water absorption coefficient and low tissue pervasion, to limit thermal injury. The 1470 nm wavelength of the diode laser is absorbed by water 40 times more effectively than the 980 nm wavelength. We conducted this study to evaluate the efficacy and safety of PLDD using a 1470 nm diode laser. We retrospectively reviewed the clinical data of 27 patients with radicular pain who underwent PLDD for the treatment of contained lumbar disc herniation during a 12-month period. The 1470 nm diode laser produces smaller local lesions, but greater tissue variations around the nucleus pulposus. This higher affinity for water lessens the formation of a carbonization zone, which results in less thermal injury of the adjacent nervous tissue. According to the MacNab criteria, 85.2% of the cases were improved at 6-month follow-up. Pain decreased from VAS 8.1 preoperatively to VAS 3.1 postoperatively. There is no consensus in the international literature regarding the ideal wavelength. Our results support the conclusion that PLDD using a 1470 nm diode laser is a safe and effective minimally invasive technique for patients with radicular pain affected by contained herniated lumbar discs.

Surgical treatment of solitary intradural extramedullary spinal cord metastases from solid cancers of non-neurogenic origin. A multicenter study

PURPOSE

Intradural extramedullary spinal metastases (IESM) represent an extremely rare manifestation of systemic cancer. We evaluated the surgical indications, complications and outcome in a series of 43 patients with solitary intradural extramedullary metastases originating from solid cancer of non-neurogenic origin.

METHODS

Patients' age, histopathological diagnoses of primary cancer, tumor size, spinal location, and extramedullary tumor dissemination were collected. Preoperative functional status, pre- and post-operative neurological status, extent of the tumor resection were also analyzed.

RESULTS

The majority of IEMS occurred in the thoracic area, with the most common presenting symptoms ranging from motor (76.7%) to sensory (72%) deficits. Gross total resection was achieved in 55.8% of cases, while In 44.2% of patients a subtotal resection was performed due to strong adherence between the tumor and neural tissue. After surgery, 72.1% of patients exhibited improvement of symptoms in terms of pain relief and partial recovery of motor and/or sensory deficits, while neurologic functional status was severely affected postoperatively in 3 patients.

CONCLUSION

Although there was no statistical significance between the different parameters and overall survival, KPS and the presence of other metastases were the strongest prognostic factors for overall survival and postoperative neurologic outcome.

Hybrid Raman-erbium random fiber laser with a half open cavity assisted by artificially controlled backscattering fiber reflectors

A hybrid Raman-erbium random fiber laser with a half-open cavity assisted by chirped artificially controlled backscattering fiber reflectors is presented. A combination of a 2.4 km-long dispersion compensating fiber with two highly erbium-doped fiber pieces of 5 m length were used as gain media. A single random laser emission line centered at 1553.8 nm with an optical signal to noise ratio of 47 dB were obtained when pumped at 37.5 dBm. A full width at half maximum of 1 nm and a 100% confidence level output power instability as low as 0.08 dB were measured. The utilization of the new laser cavity as a temperature and strain sensor is also experimentally studied.

Flow ventricular catheters for shunted hydrocephalus: initial clinical results

BACKGROUND

The non-homogenous flow of the cerebrospinal fluid within the ventricular catheter is one of the causative factors in shunt obstructions during the treatment of hydrocephalus. Previously, we studied the flow in ventricular catheters under the steady and pulsatile boundary conditions by means of computational fluid dynamics (CFD) in three-dimensional paradigms. Subsequently, several catheter designs with homogeneous flow patterns were developed out of which one prototype was chosen after a validation study.

OBJECTIVE

To test the effectiveness of the flow ventricular catheter in a prospective, multicenter, comparative study.

METHODS

Eligible centers were three pediatric hospitals: two with sole adult practice and one a mixed pediatric-adult. Standard silicone material was used to develop a parametric catheter model with homogenous flow characteristics. The flow catheters were inserted in pediatric (n = 30) and adult (n = 10) patients with all types of hydrocephalus. Simultaneously, regular ventricular catheters were inserted in another 43 control patients in the participating centers. Catheter positioning was standardized according to the Schaumann and Thomale classification.

RESULTS

All ventricular catheters had a cephalad grade I or II positioning, and caudally, its extension had a peritoneal location. Programmable valves were utilized in 70% and antisiphon devices in 20% of the cases. Regular differential pressure valves were utilized in the remaining. No case of flow catheter obstruction was identified during a mean follow-up period of 2 years at the time of this writing. There were four catheter obstructions in the control cohort, all pediatric cases, during the first year. Shunt infections occurred in two cases in the control group, while there was one recurrent case of adult ventriculitis in the flow catheter group.

CONCLUSIONS

This prototype model represents the next generation of ventricular catheters with a homogeneous flow pattern. The flow catheter can be inserted safely in hydrocephalic patients, and this preliminary prospective comparative study showed a possible obstruction-free functionality.

Surgical treatment of intramedullary spinal cord metastases: functional outcome and complications-a multicenter study

Intramedullary spinal cord metastasis (ISCM) is a rare event in the course of advanced malignancy. Management of these lesions remains controversial. Recently, surgery for ISCM has been advocated for selected patients. We performed a retrospective analysis of the clinical course, complications, and outcome of 30 patients surgically treated for ISCM. Patients' age, histopathological diagnoses of primary cancer, tumor size, spinal location, and extramedullary tumor dissemination were collected. Preoperative functional status, pre- and postoperative neurological status, and extent of the tumor resection were also analyzed. Predominant tumor location was thoracic, followed by cervical and conus medullaris. Lung cancer constituted the majority of primary malignancies. In 9 cases, one of the indications for spinal surgery was to obtain a histopathological diagnosis. On admission, all patients presented with neurological symptoms suggestive of myelopathy. After surgery, 18 patients exhibited improvement of symptoms in terms of pain relief and partial recovery of motor and/or sensory deficits; 6 patients were unchanged, while 6 patients exhibited postoperative deterioration. Median survival time after surgery was 9.9 months. Age > 70 years old, presence of systemic metastases, preoperative neurological non functional status, and lung cancer as primary tumor were all factors associated with a worse survival prognosis. This study did not show a clear survival difference between gross total and subtotal ISCM tumor resection. Patients who underwent gross total resection had a worse functional outcome with respect to patients with only partial resection. Gross total resection with low morbidity must be the surgical target, but when not possible, subtotal resection and adjuvant therapy are a valid therapeutic option.

Oblique Lateral Retroperitoneal Lumbar Pre-Psoas Approach for Vertebrectomy in Cancer Patients: Surgical Technique

Due to the longer survival of cancer patients secondary to improved systemic treatments, there has been a recent increase in the incidence of spinal metastases. Metastatic disease involves the anterior vertebral body in 80% of cases. Progressive osseous invasion may result in pathologic vertebral fractures and neural structure compression. Surgical indications are spinal cord and cauda equina compression or spinal instability in patients with an expected survival of at least 6 months. Tumor resection and spine reconstruction in the lumbar region are technically demanding. Several approaches have recently been developed to access the lumbar spine: anterior lumbar approach (ALIF), lateral and extreme lateral transpsoas lumbar approach (LLIF, XLIF, DLIF), and oblique retroperitoneal lumbar pre-psoas approach (OLIF). Each technique has its advantages and drawbacks. OLIF is an emerging procedure that has progressively been used by spine surgeons. The retroperitoneal space allows direct access to the vertebra, thus avoiding injury to the paraspinal muscles, psoas muscle, and lumbar plexus. Between 2005 and 2017, 14 patients underwent somatectomy and spinal reconstruction using an oblique retroperitoneal lumbar pre-psoas approach at our institution. All were affected by lumbar vertebral metastases from solid and hematological tumors, and all presented a Tokuhashi score ≥ 12. L3 vertebral body was involved in 7 cases, L1 was involved in 3, L2 was involved in 2, and L4 was involved in 2. All patients underwent a lateral retroperitoneal approach to achieve vertebrectomy and spinal reconstruction with a cage. Spinal fixation was completed with pedicle screws and rods in 4 cases. No neurological worsening was noted except in one patient who presented a transitory deficit of the left ileopsoas muscle. The oblique retroperitoneal lumbar pre-psoas approach may be a valuable and feasible technique that is potentially able to significantly reduce tissue trauma in patients while still making it possible to achieve corpectomy and solid reconstruction of lumbar vertebral bodies. To our knowledge, this is the first reported series of patients with lumbar spinal metastases treated with the oblique retroperitoneal lumbar pre-psoas approach.

Minimally invasive spinal fixation in an aging population with osteoporosis: clinical and radiological outcomes and safety of expandable screws versus fenestrated screws augmented with polymethylmethacrylate

OBJECTIVE

The goal of this study was to compare the clinical and radiological outcomes between fenestrated pedicle screws augmented with cement and expandable pedicle screws in percutaneous vertebral fixation surgical procedures for the treatment of degenerative and traumatic spinal diseases in aging patients with osteoporosis.

METHODS

This was a prospective, single-center study. Twenty patients each in the expandable and cement-augmented screw groups were recruited. Clinical outcomes included visual analog scale (VAS), Oswestry Disability Index (ODI), and satisfaction rates. Radiographic outcomes comprised radiological measurements on the vertebral motion segment of the treated levels. Intraoperative data including complications were collected. All patients completed the clinical and radiological outcomes. Outcomes were compared preoperatively and postoperatively.

RESULTS

An average shorter operative time was found in procedures in which expandable screws were used versus those in which cement-augmented screws were used (p < 0.001). No differences resulted in perioperative blood loss between the 2 groups. VAS and ODI scores were significantly improved in both groups after surgery. There was no significant difference between the 2 groups with respect to baseline VAS or ODI scores. The satisfaction rate of both groups was more than 85%. Radiographic outcomes also showed no significant difference in segment stability between the 2 groups. No major complications after surgery were seen. There were 4 cases (20%) of approach-related complications, all in fenestrated screw procedures in which asymptomatic cement extravasations were observed. In 1 case the authors detected a radiologically evident osteolysis around a cement-augmented screw 36 months after surgery. In another case they identified a minor loosening of an expandable screw causing local back discomfort at the 3-year follow-up.

CONCLUSIONS

Expandable pedicle screws and polymethylmethacrylate augmentation of fenestrated screws are both safe and effective techniques to increase the pullout strength of screws placed in osteoporotic spine. In this series, clinical and radiological outcomes were equivalent between the 2 groups. To the authors’ knowledge, this is the first report comparing the cement augmentation technique versus expandable screws in the treatment of aging patients with osteoporosis.

A Proposed Intention-to-Treat Anatomical Classification of Spinal Dural Tears

To clarify outcomes and develop a novel classification according to CSF fistula in a selective cohort with intraoperative spinal dural tear, we examined 72 consecutive patients who underwent spinal dural repair after microdiscectomy (n=42) or lumbar spinal decompression (n=30). Group 1 consisted of 25 patients with Type I (mild) dural tear who were treated with either tissue-glue-coated collagen sponge or fibrin glue. Group 2 consisted of 26 patients with Type II (moderate) dural tear who were treated with both tissue-glue-coated collagen sponge and fibrin glue. Group 3 consisted of 21 patients with Type III (severe) dural tear who were treated with polypropylene suture along with tissue-glue-coated collagen sponge and/or fibrin glue. Evident postoperative internal or external CSF leak was used to determine the patient's postoperative result. Postoperative internal or external CSF leak was not evident during a minimum 1-year follow-up in Group 1. In contrast, internal CSF leak was evident in both Groups 2 (n=3) and 3 (n=3) during the same follow-up. No external CSF leak was noted in any of the patients. Three patients underwent re-do spinal surgery for CSF leak repair. Patients in all groups satisfactorily avoided CSF leak. According to the intraoperative findings of a distinct dural tear, patients can be treated adequately with a specific surgical technique.

Step-by-step Illustration of the Cranial Bifrontal Approach

Based on experience with several hundreds of adult and pediatric patients in whom the cranial bifrontal approach was used to achieve different surgical objectives, this paper describes this approach in a step-by-step manner with illustrations. This is a basic approach to the anterior cranial fossa that enables the preservation of most bridging veins. The bifrontal approach, whether basal, interhemispheric, or both, allows a wider bilateral operative field with better orientation and views of important neural structures and perforating arteries, without needing to be combined with other approaches. The following description should be regarded as a basic technique to arrive at a definite location within the anterior cranial compartment and beyond, rather than as rigid steps that must be followed rigorously. These illustrations are intended to present essential principles of a standard bifrontal approach. Since the same principles can be followed for every bifrontal approach, this technique along with the surgical results can be constantly improved.

Pulsatile flow in ventricular catheters for hydrocephalus

The obstruction of ventricular catheters (VCs) is a major problem in the standard treatment of hydrocephalus, the flow pattern of the cerebrospinal fluid (CSF) being one important factor thereof. As a first approach to this problem, some of the authors studied previously the CSF flow through VCs under time-independent boundary conditions by means of computational fluid dynamics in three-dimensional models. This allowed us to derive a few basic principles which led to designs with improved flow patterns regarding the obstruction problem. However, the flow of the CSF has actually a pulsatile nature because of the heart beating and blood flow. To address this fact, here we extend our previous computational study to models with oscillatory boundary conditions. The new results will be compared with the results for constant flows and discussed. It turns out that the corrections due to the pulsatility of the CSF are quantitatively small, which reinforces our previous findings and conclusions.This article is part of the themed issue 'Mathematical methods in medicine: neuroscience, cardiology and pathology'.

Biosurgical Hemostatic Agents in Neurosurgical Intracranial Procedures

Intraoperative hemostasis during neurosurgical procedures is one of the most important aspects of intracranial surgery. Hemostasis is mandatory to keep a clean operative field and to prevent blood loss and postoperative hemorrhage. In neurosurgical practice, biosurgical hemostatic agents have proved to be extremely useful to complete the more classic use of electrocoagulation. During recent years, many biosurgical topical hemostatic agents were created. Although routinely used during neurosurgical procedures, there is still a great deal of confusion concerning optimal use of these products, because of the wide range of products, as absorbable topical agents, antifibrinolytics agents, fibrin sealants and hemostatic matrix, which perform their hemostatic action in different ways. The choice of the hemostatic agent and the strategy for local hemostasis are correlated with the neurosurgical approach, the source of bleeding, and the neurosurgeon's practice. In this study, the authors review all the different sources of bleeding during intracranial surgical approaches and analyze how to best choose the right topical hemostatic agent to stop bleeding, from the beginning of the surgical approach to the end of the extradural hemostasis after dural closure, along all the steps of the neurosurgical procedure.

Influence of the hole geometry on the flow distribution in ventricular catheters for hydrocephalus

BACKGROUND

Hydrocephalus is a medical condition consisting of an abnormal accumulation of cerebrospinal fluid within the brain. A catheter is inserted in one of the brain ventricles and then connected to an external valve to drain the excess of cerebrospinal fluid. The main drawback of this technique is that, over time, the ventricular catheter ends up getting blocked by the cells and macromolecules present in the cerebrospinal fluid. A crucial factor influencing this obstruction is a non-uniform flow pattern through the catheter, since it facilitates adhesion of suspended particles to the walls. In this paper we focus on the effects that tilted holes as well as conical holes have on the flow distribution and shear stress.

METHODS

We have carried out 3D computational simulations to study the effect of the hole geometry on the cerebrospinal fluid flow through ventricular catheters. All the simulations were done with the OpenFOAM® toolbox. In particular, three different groups of models were investigated by varying (i) the tilt angles of the holes, (ii) the inner and outer diameters of the holes, and (iii) the distances between the so-called hole segments.

RESULTS

The replacement of cylindrical holes by conical holes was found to have a strong influence on the flow distribution and to lower slightly the shear stress. Tilted holes did not involve flow distribution changes when the hole segments are sufficiently separated, but the mean shear stress was certainly reduced.

CONCLUSIONS

The authors present new results about the behavior of the fluid flow through ventricular catheters. These results complete earlier work on this topic by adding the influence of the hole geometry. The overall objective pursued by this research is to provide guidelines to improve existing commercially available ventricular catheters.

Failure rates and complications of interspinous process decompression devices: a European multicenter study

OBJECT

Spacers placed between the lumbar spinous processes represent a promising surgical treatment alternative for a variety of spinal pathologies. They provide an unloading distractive force to the stenotic motion segment, restoring foraminal height, and have the potential to relieve symptoms of degenerative disc disease. The authors performed a retrospective, multicenter nonrandomized study consisting of 1108 patients to evaluate implant survival and failure modes after the implantation of 8 different interspinous process devices (IPDs).

METHODS

The medical records of patients who had undergone placement of an IPD were retrospectively evaluated, and demographic information, diagnosis, and preoperative pain levels were recorded. Preoperative and postoperative clinical assessments in the patients were based on the visual analog scale. A minimum of 3 years after IPD placement, information on long-term outcomes was obtained from additional follow-up or from patient medical and radiological records.

RESULTS

One thousand one hundred eight patients affected by symptomatic 1- or 2-level segmental lumbar spine degenerative disease underwent placement of an IPD. The complication rate was 7.8%. There were 27 fractures of the spinous process and 23 dura mater tears with CSF leakage. The ultimate failure rate requiring additional surgery was 9.6%. The reasons for revision, which always involved removal of the original implant, were acute worsening of low-back pain or lack of improvement (45 cases), recurrence of symptoms after an initial good outcome (42 cases), and implant dislocation (20 cases).

CONCLUSIONS

The IPD is not a substitute for a more invasive 3-column fusion procedure in cases of major instability and spondylolisthesis. Overdistraction, poor bone density, and poor patient selection may all be factors in the development of complications. Preoperatively, careful attention should be paid to bone density, appropriate implant size, and optimal patient selection.

Basic cerebrospinal fluid flow patterns in ventricular catheters prototypes

OBJECT

A previous study by computational fluid dynamics (CFD) of the three-dimensional (3-D) flow in ventricular catheters (VC) disclosed that most of the total fluid mass flows through the catheter's most proximal holes in commercially available VC. The aim of the present study is to investigate basic flow patterns in VC prototypes.

METHODS

The general procedure for the development of a CFD model calls for transforming the physical dimensions of the system to be studied into a virtual wire-frame model which provides the coordinates for the virtual space of a CFD mesh, in this case, a VC. The incompressible Navier-Stokes equations, a system of strongly coupled, nonlinear, partial differential conservation equations governing the motion of the flow field, are then solved numerically. New designs of VC, e.g., with novel hole configurations, can then be readily modeled, and the corresponding flow pattern computed in an automated way. Specially modified VCs were used for benchmark experimental testing.

RESULTS

Three distinct types of flow pattern in prototype models of VC were obtained by varying specific parameters of the catheter design, like the number of holes in the drainage segments and the distance between them. Specifically, we show how to equalize and reverse the flow pattern through the different VC drainage segments by choosing appropriate parameters.

CONCLUSIONS

The flow pattern in prototype catheters is determined by the number of holes, the hole diameter, the ratio hole/segment, and the distance between hole segments. The application of basic design principles of VC may help to develop new catheters with better flow circulation, thus reducing the possibility of becoming occluded.

A Clinico-pathologic Study of Oxidized Cellulose as Topical Hemostatic Agent in Neurosurgery

Hemostasis is extremely important in neurosurgical procedures to prevent major postoperative bleedings and their catastrophic consequences. Emoxicel TAF Retilight (Bioster, a.s., Czech Republic) is a sterile, resorbable, hemostatic reticulum, mainly used to stop capillary and venous bleeding. The textile form of the hemostatic material allows, in several cases, perfect adjustment to the varied shape of the surgical cavities and of the epidural space to which it adheres when wet. Hemostatic effect is rapid, and complete hemostasis can be achieved in several minutes after application. This topical hemostatic agent is biocompatible, biodegradable, and highly resorbable. It has a hemostatic and antimicrobic effect. The main aim of this study was to verify the efficacy, broadness of use, and safety of this topical hemostatic in neurosurgical procedures. A total of 43 cases were included, 18 cranial and 25 spinal, and in only one case a postoperative epidural bleeding was reported. A histopathologic study of the hemostatic was performed. No allergic reactions were reported. Emoxicel was useful not only in stopping minor bleeding, but also for bleeding prevention in the postoperative period.

Role of EVICEL Fibrin Sealant to Assist Hemostasis in Cranial and Spinal Epidural Space: A Neurosurgical Clinical Study

A variety of techniques have been used to stop venous bleeding from the cranial and spinal epidural space. These generally consist of packing with oxidized regenerated cellulose, fibrillar collagen, and so forth, and in cranial surgery, tack-up sutures. Bipolar coagulation may also be used to control bleeding from spinal venous plexus, but it may bear the risk of healthy nervous tissue injury: dissipation of heat from the tips of the bipolar forceps may induce thermal injury to adjacent neural structures. Quick and safe hemostasis reduces the duration of surgery. Efficient control of bleeding is also a prerequisite for the realization of the planned therapeutic procedure, that is, the result of surgery, and can thereby reduce perioperative morbidity. Fibrin sealant is safely used to increase hemostasis and to treat cerebrospinal leakage. Between January 2014 and March 2015, the authors used injection of fibrin sealant (EVICEL®, Johnson & Johnson Wound Management, Somerville, NJ) into the cranial and spinal epidural space to assist in hemostasis in 97 patients. EVICEL injection was used in 81 cases of cranial surgery and 16 cases of spinal surgery. When the venous bleeding continued from the epidural space after packing with classical hemostatic agents, fibrin sealant was used to stop venous bleeding. When arterial bleeding was present, fibrin sealant was not used. In all cases, the results were judged to be excellent with stoppage of epidural bleeding, or good with mild persistent oozing. During the 10-minute observation period, no patients treated with EVICEL required additional hemostatic measures. No complications related to the fibrin glue were encountered.

Use of Tissue-Glue–Coated Collagen Sponge (TachoSil) to Repair Minor Cerebral Dural Venous Sinus Lacerations

BACKGROUND

Significant hemorrhage may occur from the cerebral venous sinuses during the dural separation from the bone flap, particularly in elderly patients. It is important to achieve an urgent hemostatic control.

OBJECTIVE

To evaluate the efficacy and safety of a new fixed combination tissue sealant (TachoSil) in patients with bleeding from lacerations of cerebral venous sinuses.

METHODS

Between September 2012 and June 2014, 57 patients (39 female, 18 male) presenting with iatrogenic tears of the superior sagittal or transverse/sigmoid sinuses were treated with a topical fibrin sealant patch. Intraoperative source of bleeding, time to bleeding control, quantity of sealant sponge used, and postoperative complications were evaluated. Time to hemostasis was used as the primary end point.

RESULTS

Effective hemostasis, defined as cessation of bleeding after application of topical hemostatic agent, was achieved no later than 4 minutes in all except 5 patients with persistent bleeding from the sinus. In these 5 cases, bleeding was finally stopped after application of a new larger layer of TachoSil Sponge (2 cases) or gelatin hemostatic matrix (2 cases) or fibrin glue (1 case) over the layer of TachoSil.

CONCLUSION

We report our experience with a new hemostasis technique to manage bleeding from iatrogenic lacerations of cerebral venous sinuses.

New designs of ventricular catheters for hydrocephalus by 3-D computational fluid dynamics

INTRODUCTION

Based on a landmark study by Lin et al. of the two-dimensional flow in ventricular catheters (VCs) via computational fluid dynamics (CFD), we studied in a previous paper the three-dimensional flow patterns of five commercially available VC. We found that the drainage of the cerebrospinal fluid (CSF) mostly occurs through the catheter's most proximal holes. In this paper, we design five VC prototypes with equalized flow characteristics.

METHODS

We study five prototypes of VC by means of CFD in three-dimensional (3-D) automated models and compare the fluid-mechanical results with our previous study of currently in use VC. The general procedure for the development of a CFD model calls for transforming the physical dimensions of the system to be studied into a virtual wire-frame model, which provides the coordinates for the virtual space of a CFD mesh. The incompressible Navier-Stokes equations, a system of strongly coupled, nonlinear, partial differential equations governing the motion of the flow field, are then solved numerically.

RESULTS

By varying the number of drainage holes and the ratio hole/segment, we improved flow characteristics in five prototypes of VC. Models 1, 2, and 3 have a distal to proximal decreasing flow. Model 4 has an inverse flow to the previous ones, that is, a distal to proximal increasing flow, while model 5 has a constant flow over the segments.

CONCLUSIONS

New catheter designs with variable hole diameter, number of holes, and ratio hole/segment along the catheter allow the fluid to enter the catheter more uniformly along its length, thus reducing the chance that the catheter becomes occluded.

(EVICEL) for Augmentation of Dural Closure: Results of a Preliminary Clinical Study

The authors prospectively evaluated the safety and efficacy of a new fibrin sealant in patients undergoing emergency and elective cranial/spinal surgery with documented cerebrospinal fluid (CSF) leakage after sutured dural repair. This study was designed as a prospective, nonrandomized clinical trial. EVICEL® Fibrin Sealant (Johnson & Johnson, Somerville, NJ) was used in 72 patients with documented intraoperative CSF leakage after neurosurgical dural repair for a variety of pathologies. Intraoperative CSF leakage was either spontaneous or induced by a Valsalva maneuver. Patients were monitored for 1 month postoperatively with physical examinations, clinical laboratory analyses, and diagnostic imaging (CT or MRI). The sealant was effective in closing intraoperative CSF leakage in all patients but one. There were no sealant-related adverse events, and all clinical outcomes were consistent with expectations for seriously ill patients undergoing prolonged neurosurgical procedures. EVICEL® Fibrin Sealant provides a safe and effective watertight closure when used as an adjunct to sutured dural repair during cranial surgery.

Use of a Thrombin-gelatin Hemostatic Matrix (Surgiflo) in Spinal Surgery

A variety of techniques have been used to stop venous bleeding from the spinal epidural space. These generally consist of packing with Surgicel®, fibrillar collagen or Gelfoam®. Bipolar coagulation may also be used to control bleeding from spinal venous plexus, but it may bear the risk of healthy nervous tissue injury: dissipation of heat from the tips of the bipolar forceps may induce thermal injury to adjacent neural structures. In the case of intraspinal bleeding, quick and safe hemostasis is mandatory to ensure adequate visualization and safe preparation so as to avoid damaging nerves and spinal medulla. In addition, quick and safe hemostasis reduces the duration of surgery. Efficient control of bleeding can thereby reduce perioperative morbidity. During 6 months, the authors performed more than 170 major spinal surgeries, and in 67 procedures they used injection of thrombin-gelatin hemostatic matrix (Surgiflo, Johnson & Johnson Wound Management, Somerville, NJ) into spinal epidural space to assist in hemostasis. When the venous bleeding continued from the epidural space after packing with hemostatic agents as Surgicel and fibrillar collagen, gelatin matrix was used to stop venous bleeding. In all cases, the results were judged to be excellent, with immediate stoppage of epidural bleeding, or good. No complications related to the thrombin-gelatin hemostatic matrix were encountered. The thrombin-gelatin matrix could represent a valuable tool when other hemostatic strategies are ineffective or suboptimal. It is safe and biocompatible when compared with hemostatic agents currently in use. This is the first study reporting the use of Surgiflo hemostatic matrix in spinal surgery.

Safety of intraoperative electrophysiological monitoring (TES and EMG) for spinal and cranial lesions

Intraoperative motor evoked potentials (MEP) and electromyography (EMG) monitoring in patients with spinal and cranial lesions is a valuable tool for prevention of postoperative motor deficits. The purpose of this study was to determine whether electrophysiological monitoring during skull base, spinal cord, and spinal surgery might be useful for predicting postoperative motor deterioration. From January 2012 to March 2013, thirty-three consecutive patients were studied using intraoperative monitoring (Nuvasive NV-M5 System) to check the integrity of brainstem, spinal cord, and nerve roots, recording transcranial motor evoked potentials (TcMEPs) and electromyography. Changes in MEPs and EMGs were related to postoperative deficits. Preoperative diagnosis included skull base and brainstem lesions (6 patients), spinal tumors (11 patients), spinal deformity (16 cases). Using TcMEPs and EMG is a practicable and safe method. MEPs are useful in any surgery in which the brainstem and spinal cord are at risk. EMG stimulation helps to identify an optimal trans-psoas entry point for an extreme lateral lumbar interbody fusion (XLIF) approach to protect against potential nerve injury. This neural navigation technique via a surgeon-interpreted interface assists the surgical team in safely removing lesions and accessing the intervertebral disc space for minimally invasive spinal procedures.

"Triple R" tonsillar technique for the management of adult Chiari I malformation: surgical note

BACKGROUND

Chiari type I malformation is a congenital disorder that is characterized by the caudal extension of the cerebellar tonsils through the foramen magnum into the cervical canal and by a reduced posterior fossa volume.

METHODS

We report our surgical technique of reposition, reduction, or resection of the cerebellar tonsils for the management of Chiari I malformation. The procedure was performed in 22 adult patients, in three different centers, with a mean age of 37 years. Clinical complaints included headaches, nuchalgia, vertigo, and upper-limb weakness or numbness. Seven patients had cervical syringomyelia. Symptoms developed within a mean time of 36 months (range, 12-70 months).

RESULTS

The cerebellar tonsils were exposed through a dura mater-arachnoid incision at the atlanto-occipital space after a 0.5-cm rimming craniectomy of the occipital bone in all patients. In seven patients the tonsils were resected, in other seven were reduced by subpial coagulation and aspiration, and in the remaining eight patients the tonsils were repositioned after coagulating their surfaces. Three patients had also a posterior fossa arachnoid cyst that was fenestrated in two of them. All patients improved postoperatively. Syringomyelia was reduced in five of seven patients. The mean length of the follow-up period was 12 months.

CONCLUSIONS

Selective reposition, reduction, or resection of herniated cerebellar tonsils may improve symptoms in adult patients with Chiari I malformation.

Accidental head trauma during care activities in the first year of life: a neurosurgical comparative study

OBJECTIVES

This study aims to describe clinical-epidemiological data regarding accidental fall injuries occurring during homecare activities among children up to 1 year of age and to compare their outcomes according to the type of trauma.

METHODS

We searched four different hospital databases on head injuries from 1999 to 2009. Patients recorded under the descriptors "accidental fall" and "home-related" in the subtext were selected. Patients were classified into two groups: those who flipped over and fell from a changing table (n = 253) and those who fell from the bed sustaining a direct impact from the floor (n = 483).

RESULTS

There was no difference between both groups with respect to age, gender, and Glasgow Coma Scale score. However, children who suffered injuries after an accidental fall from the changing table were more likely to require surgery (26/483 vs. 57/253, p < 0.0001), had a mean longer length of stay (LOS, 4 vs. 1 day), and a higher incidence of depressed skull fractures (12/483 vs. 24/253, p < 0.0001). Children with a direct impact from the floor after falling off the bed were expected to suffer from simple linear skull fractures, while those who flipped over the changing table were more likely to present facial, soft tissue, or skeletal injuries.

CONCLUSIONS

Children who flipped over a changing table during their homecare activities were more likely to require surgery, showed a higher morbidity, and showed a longer LOS than those who fell down from the bed. These results probably reflect the different impact energy according to each injury mechanism.

Wind instruments and headaches

The authors illustrate the cases of two children with headaches, one diagnosed with Chiari type 1 malformation and the other with hydrocephalus, who played wind instruments. Both patients manifested that their headaches worsened with the efforts made during playing their musical instruments. We briefly comment on the probable role played by this activity on the patients' intracranial pressure and hypothesize that the headaches might be influenced by increases in their intracranial pressure related to Valsalva maneuvers. We had serious doubts on if we should advise our young patients about giving up playing their music instruments.

Safety biocompatibility of gelatin hemostatic matrix (Floseal and Surgiflo) in neurosurgical procedures

Adequate hemostasis in cranial and spinal surgery is of paramount importance in a neurosurgeon's daily practice. Generalized ooze bleeding from the surgical wall cavities, coming from the dura mater or nervous tissue may be troublesome and may limit visualization in minimally invasive neurosurgery. Hemostatic matrix is a mixture of a flowable gelatin matrix (bovine or porcine) and a thrombin component mixed together. A total of 318 patients undergoing cranial, craniospinal, and spinal procedure with the use of gelatin hemostatic matrix (Floseal and Surgiflo) were enrolled in this clinical study. We compared the different hemostatic techniques using the gelatin hemostatic matrix, and investigated indications, time to bleeding control, and its efficacy and safety in neurosurgery.

Portraying disease: Sorolla's Sad Legacy

In 1899, the Spanish painter Joaquín Sorolla represented, in a large canvas, a group of children probably with sequels of poliomyelitis bathing at Valencia's beach. The title of this painting was Sad Legacy. This work contributed to the international diffusion of Sorolla's artistic creation. We briefly report some facts regarding the painter and his work referring to those portraits of children and especially of sick children.

Association between cavernous angioma and cerebral glioma. Report of two cases and literature review of so-called angiogliomas

The association between vascular malformations and cerebral gliomas is unusual. While the association between cavernous angioma with gliomatous lesions is even more rare, it is considered by certain authors to be a particular pathological entity termed angioglioma. The authors report on two cases of association of a cavernous angioma with a ganglioglioma and an oligodendroglioma respectively. Subsequent review of the literature on the so-called angiogliomas was conducted. In the author's opinion, the entity of angiogliomas represents a general spectrum of angiomatous neoplasms that include gliomatous tumors, in the majority low-grade gliomas, associated with a major vascular component.

Pediatric diseases in Juan Carreño de Miranda's paintings

Pediatric obesity has become a widespread problem of health in developed countries. Overweight in the pediatric population obeys to a variety of causes. A few of Carreño de Miranda's paintings show pathological conditions occurring in children of his epoch. We briefly illustrate the significance of Carreño's paintings that portray some of these diseases. Two of his best-known works constitute an artistic representation of childhood obesity.

Simple, effective, supine positioning for the retrosigmoid approach

BACKGROUND

The retrosigmoid approach is often used for posterior fossa pathology. Many variations of positioning exist. Here, we report a simple, safe, and quick positioning technique which maximizes patient safety, surgeon comfort, and intraoperative view.

METHODS

We reviewed the senior author's prospective surgical database for retrosigmoid approaches to the posterior fossa and noted any complications or difficult exposures.

RESULTS

Over 970 retrosigmoid operations were performed over the course of 19 years. There were no positioning-related complications and no aborted surgeries due to inadequate exposure. No normal cerebellum was ever resected to increase exposure and no retractor was ever used in the posterior fossa.

CONCLUSIONS

Supine positioning for the retrosigmoid approach is an excellent and safe positioning alternative.

Degenerative lumbar spinal stenosis with neurogenic intermittent claudication and treatment with the Aperius PercLID System: a preliminary report

OBJECT

The aim of this study was to evaluate whether clinical improvement is noticeable after a minimally invasive procedure such as that used with the Aperius PercLID System in patients with degenerative lumbar spinal stenosis (DLSS) and neurogenic intermittent claudication (NIC).

METHODS

The patients were treated with the aforementioned system at 3 different centers. The initial requirement to be included in the study was a minimum follow-up of 12 months. The authors studied 40 cases of DLSS in patients with NIC (age 72.7 +/- 8.08 years). Symptom severity, physical function, quality of life, and self-rated pain were assessed preoperatively and at the 12-month follow-up using the Zurich Claudication Questionnaire (ZCQ) and a visual analog scale. The procedure was conducted under spinal (35 patients) or local (5 patients) anesthesia, using biplanar fluoroscopy for visualization.

RESULTS

Single-level treatment was performed in 28 patients and 2-level treatment was performed in 12 patients. Based on time recordings in 24 cases, the mean procedural time was 19.9 +/- 5.0 minutes. The mean pain visual analog scale score improved significantly from 8.1 +/- 2.19 at baseline to 3.44 +/- 2.89 at the 1-year follow-up. The ZCQ score for patient satisfaction showed 90% of the patients being satisfied with the procedure. The mean rates of improvement in ZCQ score for symptom severity and physical function at 1 year were 38.7 +/- 33.3% and 33.8 +/- 29.7%, respectively, and both proved to be statistically significant. Most improvement was seen in mobility, pain/discomfort, and ability for self-care.

CONCLUSIONS

In this preliminary study, the Aperius system provided clinically significant improvement after 1 year of follow-up in patients older than 65 years with DLSS and NIC.

Hemostatic matrix sealant in neurosurgery: a clinical and imaging study

OBJECT

The aim of this study was to investigate prospectively the efficacy and safety of Floseal hemostatic matrix.

METHODS

A total of 214 patients (87 males, 127 females; mean age 56.2 years) undergoing cranial (71.4%), craniospinal (0.9%), and spinal (27.5%) procedures with the use of gelatin thrombin hemostatic matrix (Floseal) were included in this prospective study. The indications for its use, surgical techniques, time to bleeding control, and associated complications were recorded.

RESULTS

Effective hemostasis, defined as cessation of bleeding, was achieved no later than 3 min after topical agent application in all patients except in 11 cases, in which the hemostatic application was repeated. Rebleeding was disclosed in four patients 1 day after initial surgery. In one case, an intracerebral abscess developed after a malignant glioma removal. No other patient developed allergic reactions or local or systemic complications associated with the hemostatic sealant.

CONCLUSION

In this study, matrix hemostatic sealant helped to control operative bleeding in cranial and spinal surgery, reducing damage to the surrounding healthy nervous tissue while shortening surgical timing. Other than safe, the immediate hemostatic effect is an advantage in the settings of refractory bleeding.

Surgical treatment of intracranial Erdheim-Chester disease

We review the clinical presentation, radiological and histological characteristics, and the natural history, of intracranial Erdheim-Chester disease (ECD). ECD is a rare form of non-Langerhans histiocytosis that affects multiple organs. It is clinically characterized by leg pain, exophthalmos and diabetes insipidus (DI). Central nervous system involvement is rare, with only 27 patients reported in the international literature. DI and cerebellar signs represent the most common neurological symptoms. Its treatment is controversial. Intracranial surgical procedures for ECD have been reported in 11 patients with a complete surgical resection performed in six, and an intracerebral biopsy performed in five patients. In seven patients the cranial procedures represented the initial diagnostic method. Surgical resection and radiation therapy have been used in the further management of these cerebral lesions.