No abstract available
Editorial: Cerebrospinal fluid physiology
01-10-2019 – Samy, Ravi N.
No abstract available
Physiology of cerebrospinal fluid circulation
01-10-2019 – Shapey, Jonathan; Toma, A.; Saeed, S.R.
Purpose of review This article describes the physiology of cerebrospinal fluid (CSF). We review current evidence and new concepts relating to CSF physiology with respect to CSF secretion, circulation and resorption and we highlight key pathophysiological associations including the relationship between CSF and intracranial pressure.
Recent findings CSF secretion occurs primarily via the choroid plexus. Various transport mechanisms facilitate CSF secretion but the role Aquaporins play in this process is a recent discovery and an area of ongoing research. CSF circulation is a dynamic process but the importance of the perivascular ‘Glymphatic system’ and extraarachnoidal pathways of resorption are relatively new concepts.
Summary CSF physiology is dependent on various interacting factors and is critical for normal brain development and function.
Trans-mastoid approach for cerebrospinal fluid leak repair
01-10-2019 – Karkas, Alexandre; Khneisser, Edwina
Purpose of review To describe the technique and discuss the advantages and outcomes of the trans-mastoid approach (TMA) for temporal bone cerebrospinal fluid (CSF) leak.
Recent findings TMA for CSF leak repair is an alternative to middle cranial fossa approach (MCFA) with less morbidity and good outcomes.
Summary Persistent CSF leak in the temporal bone whether idiopathic, congenital or acquired, is an indication for surgery. TMA is a valid option for surgery, competing with MCFA in selected cases. Surgical technique consists of a standard mastoidectomy, exposure of the osteodural defect, and repairing it using multiple layers in an inlay and overlay fashion. Outcomes show low recurrence and complication rates with good hearing results. However, long-term follow-up should be made, as recurrences can be delayed.
Laboratory testing and imaging in the evaluation of cranial cerebrospinal fluid leaks and encephaloceles
01-10-2019 – Lipschitz, Noga; Hazenfield, J. Michael; Breen, Joseph T.; Samy, Ravi N.
Purpose of review To summarize the current evidence on the diagnostic evaluation of cranial cerebrospinal fluid (CSF) leaks and encephaloceles, including laboratory testing and imaging studies.
Recent findings The most sensitive and specific laboratory tests for CSF leak diagnosis are beta-2-transferrin and beta trace protein assays, the former more commonly used because of availability. Imaging studies used for localization of the leak site include high resolution computed tomography (HRCT) and magnetic resonance cisternography (MRC), often used in combination. Intrathecal contrast administration is reserved for complex cases with prior equivocal test results or for patients with multiple skull base defects to localize the leak site.
Summary Diagnosis of CSF leaks and encephaloceles is aimed at both confirming the leak and localizing the leak site. Future advancements in testing techniques may shorten the diagnostic process, limit the need for invasive testing, and improve the safety of such testing in indicated cases.
The evolution of presenting signs and symptoms of lateral skull base cerebrospinal fluid leaks
01-10-2019 – Naples, James G.; Shah, Ravi R.; Ruckenstein, Michael J.
Purpose of review To review the presenting signs and symptoms of spontaneous cerebrospinal fluid (CSF) leaks of the lateral skull base.
Recent findings Research continues to demonstrate that CSF leaks from the lateral skull base are insidious, and present with subtle signs and symptoms. Patients commonly present with symptoms of aural fullness, middle ear effusion, and otorrhea following tympanostomy tube insertion that can be confused for chronic otitis media. More recently headache, pulsatile tinnitus, and dizziness/vertigo are being recorded as symptoms at presentation, which is likely a reflection of the association of spontaneous CSF leak with obesity, intracranial hypertension, and superior canal dehiscence. The presence of these less common symptoms in the setting of middle ear effusion should raise suspicion for CSF leak. The rate of meningitis in spontaneous CSF leak is not negligible, and patients should be counseled on this life-threatening risk.
Summary Spontaneous CSF leak from the lateral skull base presents with subtle signs and symptoms and remains a diagnostic challenge. Less common symptoms may represent associations with underlying comorbidities, and awareness of the increasing coincidence of diseases that accompany spontaneous CSF leak is essential to prompt diagnosis and management.
The role of obesity, sleep apnea, and elevated intracranial pressure in spontaneous cerebrospinal fluid leaks
01-10-2019 – Rabbani, Cyrus C.; Saltagi, Mohamad Z.; Nelson, Rick F.
Purpose of review Spontaneous cerebrospinal fluid (s
CSF) leaks often occurs in middle age, obese females. Here we investigate the role of obesity, idiopathic intracranial hypertension (IIH), and obstructive sleep apnea (OSA) in the pathophysiology of s
Recent findings The association of obesity and s
CSF leaks has been well established in many studies. It has now been revealed that s
CSF leak patients have thinner calvariums along with the skull base. An intracranial process likely leads to calvarium and skull base thinning in s
CSF leaks patients since this occurs independent of extracranial bone thinning and independent of obesity. OSA, which is known to cause spikes in intracranial pressure (ICP), has been found to be significantly prevalent in the s
CSF population and has been shown to lead to both calvarial and skull base thinning. Chronically elevated ICP (IIH) has also been shown to impact calvarial and skull base thicknesses.
Summary The incidence of s
CSF leaks has increased in recent decades along with an increasing rate of obesity. OSA and IIH, which are obesity-related factors and cause transient and chronic elevations in ICP, have now been implicated as critical factors leading to calvarial and skull base thinning and resultant s
Middle fossa approach for spontaneous cerebrospinal fluid fistula and encephaloceles
01-10-2019 – Tolisano, Anthony M.; Kutz, Joe Walter Jr.
Purpose of review The aim of this article is to describe the middle fossa craniotomy (MFC) approach for the repair of cerebrospinal (CSF) fistula and encephaloceles.
Recent findings The MFC approach has a greater than 93% success rate for managing CSF fistula and encephaloceles located along the tegmen tympani and tegmen mastoideum. Posterior fossa defects cannot be managed by an MFC approach. Multilayer repair with the combination of soft tissue and durable substances is preferred. Hydroxyapatite bone cement provides a durable repair of thinned or absent areas of bone with a low risk of infection. Concurrent management of symptomatic superior semicircular canal dehiscence may be readily performed. Small keyhole craniotomies with the utilization of the endoscope are possible as a means to minimize temporal lobe retraction.
Summary MFC repair of CSF fistula and encephaloceles is a highly effective approach for the repair of tegmen mastoideum and tegmen tympani defects.
Postoperative management of patients with spontaneous cerebrospinal fluid leak
01-10-2019 – Stevens, Shawn M.; Smith, Cody J.; Lawton, Michael
Purpose of review To explore key management principles and outcomes following surgical intervention for spontaneous CSF leaks of the lateral skull base.
Recent findings Outcomes following surgery for spontaneous CSF leaks of the lateral skull base depend on the surgical approach utilized. The approach reported most frequently in the literature is currently the middle fossa approach. Mean leak recurrence rates, regardless of approach, were approximately 6%. The lowest leak recurrence rates were associated with the combined middle cranial fossa-transmastoid approach. A multilayer closure was employed in all of the reviewed investigations, but the choice of reconstructive material did not significantly affect outcomes. Direct surgical complications rates, overall, were low at less than 2%. Meningitis, intracranial hemorrhage, and perioperative seizure activity were only rarely encountered. A concomitant diagnosis of idiopathic intracranial hypertension was found to be associated with increased rates of leak recurrence and sequential leak development at other skull base sites.
Summary Postoperative management of patients with spontaneous CSF leaks of the lateral skull base has unique challenges. Observation of key treatment principles can lead to good outcomes and limit morbidity. A high index of suspicion should exist for concomitant idiopathic intracranial hypertension.
Diagnosis and management of spontaneous cerebrospinal fluid fistula and encephaloceles
01-10-2019 – Kutz, Joe Walter Jr.; Tolisano, Anthony M.
Purpose of review To describe the current state in the diagnosis and management of spontaneous cerebrospinal fluid (s
CSF) fistula and encephaloceles.
Recent findings The increased incidence of obesity has resulted in more cases of s
CSF fistula and encephaloceles. Obesity results in increased intracranial pressure and a greater chance of developing a s
CSF fistula or encephalocele. Obstructive sleep apnea can also result in transient increase in intracranial pressure and has been shown to be common in patients with s
CSF fistula. Treatment of CSF fistula is usually necessary because of the increased risk of meningitis. The use of hydroxyapatite bone cements to repair the temporal bone defects has been described with a high success rate of closing the fistula and a low complication rate. Concurrent superior semicircular canal dehiscent can be seen in up to 15% of cases and should be suspected during the surgical approach to avoid potential sensorineural hearing loss and chronic imbalance.
CSF fistula and encephaloceles are an uncommon cause of hearing loss, middle ear effusion, and otorrhea, but should be recognized and repaired because of the risk of meningitis.
Update on treatment options for blast-induced hearing loss
01-10-2019 – Mizutari, Kunio
Purpose of review The incidence of blast injuries has increased, and the ear is the highest risk organ. Ear injury induced by blast exposure is important in both military and civilian conditions. The permanent hearing loss caused by blast exposure is associated with a decline in the quality of life. In this review, I describe recent therapeutic strategies for each of the ear pathologies caused by blast exposure.
Recent findings For tympanic membrane perforation after blast exposure, basic fibroblast growth factor (b
FGF) has been used as a less invasive treatment to repair the tympanic membrane. The closure rates of tympanic membrane perforations treated with b
FGF were reported to be comparable to those following conventional tympanoplasty.
For sensorineural hearing loss after blast exposure, treatment with neurotrophic factors, such as nerve growth factor (NGF) or neurotrophin-3, antioxidants, and Atoh1 induction have recently been applied, and some of them were considered for clinical application.
Summary Recent advances of therapeutics for blast-induced hearing loss, based on their pathologies, have been outlined. There are several promising therapeutic approaches for both middle and inner ear disorders after blast exposure; however, further research is needed to establish new treatments for blast-induced hearing dysfunction.
State-of-the-art methods in clinical intracochlear drug delivery
01-10-2019 – Chin, Oliver Y.; Diaz, Rodney C.
Purpose of review Increasing awareness and prevalence of disorders in hearing and balance have placed emphasis on treatment strategies. With the rapid evolution in molecular, gene, and nanotechnology, alternate delivery methods have advanced intracochlear drug delivery. This review aims to raise awareness of recent developments in technologies to augment current clinical practices.
Recent findings Intracochlear drug delivery research has expanded with the familiarity and accessibility to cochlear implantation. Various therapeutics are closely studied for both safety and efficacy as well as biologic effect. Agents including neurotrophins, antiapoptotics, cell therapy, gene therapy, and anti-inflammatory drugs are on the forefront of preclinical research. Cochlear implant electrode modification and drug administration at the time of implantation is a major focus of research. Improvements in study design have focused on overcoming barriers including elucidating the role of the blood–perilymph barrier.
Summary Inner ear drug delivery methods include systemic, intratympanic, and intracochlear administration. Therapeutic technologies aim to overcome delivery barriers and to improve overall biologic effect while minimizing toxicity. Precision of drug application through intratympanic and intracochlear administration with minimal trauma is the future of inner ear drug development.
The use of cochlear implantation in the elderly
01-10-2019 – Lally, John W.; Adams, Jason K.; Wilkerson, Brent J.
Purpose of review To evaluate the impact of cochlear implantation on hearing outcomes, quality of life, complications, and cognitive function in elderly patients.
Recent findings Nine articles published between 2014 and 2019 pertain to cochlear implantation in the elderly population. The findings conclude that cochlear implantation improves autonomy and overall quality of life in the elderly.
Summary Design: a pubmed search was employed with title search terms ‘cochlear implant,’ AND ‘elderly’ or ‘aged.’ Twenty-one articles were generated. Of the 21, articles without evidence-based findings were excluded and those published more than 5 years ago were excluded, yielding a final number of nine articles for review. Results: nine articles published on the use of cochlear implantation in the elderly were identified through the literature search between the years 2014–2019. Outcomes included quality of life, speech recognition improvement, improvement in cognitive function as defined by geriatric validated scales, outcomes of hearing rehabilitation, improvement in verbal comprehension, surgical complications, and the ability to manage the external components of the device. Conclusion: cochlear implantation improves autonomy and the quality of life in the elderly. Age should not be a factor limiting surgical decision-making, and cochlear implantation can be utilized as a well tolerated, efficient treatment option for severe-to-profound hearing loss in the elderly population.
Use of multiple free flaps in head and neck reconstruction
01-10-2019 – Hsieh, Tsung-yen; Bewley, Arnaud
Purpose of review To review the recent literature on the use of multiple flaps in head and neck reconstruction with attention to form, function, outcomes, and complications.
Recent findings Multiple free flap reconstructions are technically feasible with high flap survival rates, tolerable complication rates, and overall adequate functional and aesthetic outcomes, given the large extent of the defects and the high surgical complexity of these cases.
Summary Multiple free flap reconstructions should be considered in cases of large defects involving multiple functional regions and tissue types, which most often arises following resection of advanced malignancies. As there is mortality benefit with clear surgical margins and eradication of malignant lymph nodes, larger resections should be pursued if necessary, followed by a multiple flap reconstruction.
Reconstruction of the mandible for osteoradionecrosis
01-10-2019 – Haroun, Kareem; Coblens, Orly M.
Purpose of review To describe current standard of care for osteoradionecrosis (ORN) of the mandible and report possible future trends.
Recent findings Cutting guides may be used to reduce surgical time and possibly improve outcomes. There has also been recent investigation into the use of pentoxifylline and tocopherol or pentoxifylline, tocopherol and clodronate (a well known conservative medial regime) as a prevention for development of ORN after dental extractions and the first randomized controlled study is upcoming. Augmented reality has shown promise as a comparable and inexpensive possible alternative to cutting guides.
Summary Current standard of care involves conservative/supportive therapy with antioxidants, antibiotics, steroids, and pain control for low-grade ORN with surgery reserved for high-grade/progressive ORN with refractory to conservative therapy and with significant oral dysfunction.
Reconstruction of animal bite injuries to the head and neck
01-10-2019 – Mendoza, Joshua M.; Chi, John J.
Purpose of review The aim if this review is to provide an update on the existing literature of animal bite treatment strategies and provide a systematic approach to animal bites from presentation to reconstruction.
Recent findings Dog bites cause 80–90% of animal bites with 26.8–56.5% occurring in the head and neck. Infection rates may be as low as 5.7–9.7%. Primary closure alone is sufficient in 69.8% of dog bites within the first 24 h.
Summary Animal bite injuries to the head and neck are common, especially in the younger population. Dogs cause a majority of these bite injuries. Injuries can include simple lacerations or punctures, avulsions with tissue present, or avulsions with loss of tissue. The most common locations are the cheek, nose, and lips. It is important to gather the vaccination status of the animal and patient and to administer tetanus/rabies prophylaxis if indicated. Antibiotics are typically prescribed for 3–5 and 7–14 days for uninfected and infected wounds, respectively. These wounds require evaluation, irrigation, and occasionally debridement or repair in the operating room. The type of repair is determined based on the location and extent of injury and can range from primary closure to microsurgical replantation, skin grafts, flaps, or even facial transplantation.
Optimizing value in head and neck cancer free flap surgery
01-10-2019 – Cash, Harrison; Abouyared, Marianne; Houlton, Jeffrey J.
Purpose of review Value has become an increasingly important topic in healthcare delivery as our systems attempt to deliver increased value to patients at lower costs. This review highlights research performed regarding value for head and neck cancer reconstruction in three evolving areas: care pathway development, virtual surgical planning (VSP), and free flap versus locoregional flap reconstruction.
Recent findings Improvements in quality-driven patient care in head and neck free tissue transfer are possible in a number of areas. Care pathways and appropriate management of patients prone to comorbidities decrease hospital length of stay and readmission rates. Further, high-cost hospital stays partially driven by ICU admissions may be reduced by step-down units. Intraoperatively, VSP may reduce operative time in difficult cases and careful selection of free versus locoregional flap reconstruction may decrease cost, operative time, and complications after surgery.
Summary Head and neck reconstruction is a costly endeavor both for the patient and the healthcare system. Careful consideration of practices which may improve outcomes for patients while maximizing efficiency is necessary in our changing healthcare landscape, and providers should identify areas for improvement in their own practices. Further study within the field of head and neck oncology that are specific and data-driven are necessary.
Total nasal reconstruction: a review of the past and present, with a peak into the future
01-10-2019 – Phillips, Tim J.
Purpose of review The goal of this article is to review the complex topic of total nasal reconstruction and present a wide range of options for completing this difficult surgical procedure.
Recent findings Nasal reconstruction has a long history dating back thousands of years. Some historical techniques still exist today, including the paramedian forehead flap. The introduction of free tissue transfer and other pedicled flaps has provided multiple options for the reconstructive surgeon. The future of nasal reconstruction will include facial transplantation and likely bioengineered tissues.
Summary The principles of nasal reconstruction have gone unchanged for decades; however, the techniques to meet the principles have. The current reconstructive methods of grafts, free flaps, and pedicled flaps used to replace lining, structure, and skin will likely be used for several years to come. However, the use of facial transplantation has proved effective and bioengineered tissues present an exciting future for organ replacement.
Update on anterior skull base reconstruction
01-10-2019 – Ein, Liliana; Sargi, Zoukaa; Nicolli, Elizabeth A.
Purpose of review Anterior skull base reconstruction has rapidly evolved over the past few years as endoscopic approaches to resect tumors in this region have become more established. The present review evaluates the robust amount of new literature on this topic over the past year with particular attention to minimally invasive methods for reconstruction.
Recent findings Although vascularized local flaps remain the mainstay reconstructive choice when available for the anterior skull base, innovative techniques for all types of reconstruction, ranging from free grafts to free flaps continue to emerge.
Summary Because of the unique challenges and wide variety of options available to repair the anterior skull base with the goal to prevent or treat cerebrospinal fluid leaks, surgical expertise and experience in this field is of utmost importance.