Brent J. Benscoter

Contemporary options for lateral skull base reconstruction following tumor extirpation.

Purpose of reviewThis review is timely and relevant for several reasons. More lateral skull base tumors are being diagnosed, as the threshold to image patients with lower cranial nerve symptoms is very low. Patients are living longer and can potentially have more comorbidities that can affect wound healing. More surgical teams are attempting lateral skull base surgery. Patients with benign and malignant tumors of the lateral skull base may also be treated with radiotherapy and chemotherapy, which can have implications for wound healing. Recent findingsAbdominal fat grafting continues to be a viable option for closure of defects resulting from transtemporal skull base surgery. Hydroxyapatite cranioplasty remains controversial due to a high incidence of delayed infection. For malignant lateral skull base lesions such as advanced temporal bone and parotid malignancies, free tissue transfer is increasingly utilized, as it is reliable, is harvested outside the surgical field, and provides superior wound closure. Bone anchored hearing aids (BAHAs) can be a good option for hearing rehabilitation, whereas vistafix can reliably address auricular deformities. SummaryProper reconstruction after tumor resection in skull base surgery is important to prevent postoperative complications. This article will address contemporary reconstruction options including primary closure, abdominal fat grafting, synthetic materials, microvascular free tissue transfer, BAHA and vistafix.

Androgen treatment and recovery of function following recurrent laryngeal nerve injury in the rat

PURPOSE To investigate the effects of the androgen testosterone propionate (TP), on regeneration of the recurrent laryngeal nerve (RLN) after unilateral crush injury using assessment of vocal fold mobility (VFM) as a measure of behavioral recovery. METHODS 48 adult male rats underwent standardized crush injury of left RLN and received treatment in the form of 2 silastic capsules containing TP or controls receiving a blank capsule (untreated). Direct laryngoscopic assessment of vocal cord mobility was performed before, immediately following and 1, 2, 3, 4, 5 or 6 weeks post injury. RESULTS Treatment with TP enhanced the recovery of full VFM following crush injury of the RLN compared to controls. There was statistically significant improvement in VFM seen at the 1 and 2 week time points (p < 0.05). By 4 weeks TP-treated rats displayed a 100% recovery of VFM function, compared to only 50% by the control group. CONCLUSIONS TP enhances RLN functional recovery following a crush injury, which further supports its potential general applicability as a therapeutic agent in peripheral nerve injury.

Preauricular infratemporal fossa approach for advanced malignant parotid tumors

The aims of this study were to demonstrate the surgical technique involved in the preauricular infratemporal fossa (ITF) approach, outline the clinical indications for use of this technique, and present the results in using this approach in 159 patients with malignant parotid tumors. At the conclusion of this article, the reader should be able to understand the utility of the preauricular infratemporal fossa approach in the management of patients with advanced malignant parotid tumors.

Osseointegrated Implant Applications in Cosmetic and Functional Skull Base Rehabilitation

This study discusses the indications, outcomes, and complications in patients that underwent osseointegrated implantation for skull base rehabilitation. We conducted a retrospective review of eight patients with skull base defects who had undergone implantation of a facial prosthetic retention device ± bone-anchored hearing aid at a tertiary academic referral center. Descriptive analysis of applications, techniques, outcomes, and complications were reviewed. The majority of patients were males (n = 6) with previously diagnosed skull base malignancy (n = 5) with an average age of 46 (range, 14 to 77). All patients received an implanted facial prosthetic device either for an aural (n = 7) or orbital (n = 1) prosthesis. There were only two complications that included infection (n = 1) and implant extrusion (n = 1). Osseointegrated implantation of abutments for anchoring prosthetic devices in patients for skull base rehabilitation provides an excellent cosmetic option with minimal complications.

A Rat Model for Intracranial Facial Nerve Crush Injuries

Objective. (1) Explain the need for an animal model to study intracranial injuries to the facial nerve. (2) Describe various techniques attempted to identify and crush the intracranial segment of the facial nerve in a rat model. (3) Describe in detail a successful rat model of intracranial facial nerve crush injury. Study Design. Randomized controlled animal study. Setting. Animal laboratory. Subjects and Methods. Multiple attempts at surgical approaches to the cerebellopontine angle were attempted on cadaveric rats. Once a successful approach was derived, this was used on 19 live rats under anesthesia. Fourteen rats had a 1-minute facial nerve crush performed, and 5 had a sham surgery with complete surgical exposure of the facial nerve but no crush. Rats were followed for a 12-week duration evaluating immediate postoperative facial nerve function, complications, and survival. Results. All 14 (100%) rats that underwent surgery with crush injury had complete facial paralysis postoperatively. Complete facial paralysis was defined as loss of eye-blink reflex, flat vibrissae, and lack of vibrissae movement. The 5 sham surgery rats had complete facial function postoperatively. Surgery was performed by 2 separate surgeons with no difference in outcome between the 2. Complications occurred in only 1 animal (1/19, 5.3%), which was a corneal abrasion requiring sacrifice. Conclusion. Our group describes a consistent method for performing an intracranial crush injury in the rat. This new model and its applications in translational facial nerve research are promising, particularly with tumors or lesions at the cerebellopontine angle.

Inner Ear Effects of Canal Wall Down Mastoidectomy

Objective. To evaluate the inner ear effects of canal wall down (CWD) mastoidectomy without ossiculoplasty in the treatment of chronic otitis media (COM) with regard to sensorineural hearing loss (SNHL) and reported tinnitus and dizziness-related disability. Setting. Tertiary care academic medical center. Subjects and Methods. Prospective study of 86 patients treated by CWD mastoidectomy without ossiculoplasty for COM with or without cholesteatoma. Standard patient workup included preoperative audiogram and completion of 2 surveys: Dizziness Handicap Inventory (DHI) and Tinnitus Handicap Inventory (THI). Patients underwent repeat audiogram, DHI, and THI surveys at 4 to 6 months postoperatively. Preoperative and postoperative data were analyzed. Results. No significant SNHL occurred after CWD mastoidectomy. Thirteen patients (13/34 [38%]) had DHI improvement greater than 18 points, indicating a significant improvement in dizziness-related disability. Three patients developed new-onset postoperative dizziness complaints. Twenty patients (20/43 [46.5%]) had THI improvement greater than 7 points, indicating a significant improvement in tinnitus-related disability. Five patients developed new-onset postoperative tinnitus complaints. The odds ratio for improving DHI and THI scores after surgery was 6.6 (1.8 to 25.0) and 4.2 (95% confidence interval, 1.45% to 12.2%), respectively. Conclusion. In this study, CWD mastoidectomy without ossiculoplasty in the treatment of COM did not cause significant SNHL. In addition, using the DHI and THI measures, patient-perceived disability from dizziness and tinnitus, respectively, was shown to decrease after mastoid surgery.

Effects of Gonadal Steroids and Electrical Stimulation on Cell Survival following Intracranial Facial Nerve Injury

Objectives: The purpose of this study was to assess 1) the degree of motoneuron cell loss and 2) the combinatorial effects of electrical stimulation (ES) and testosterone propionate (TP) on cell survival following an intracranial facial nerve crush injury and 3) to compare these results to distal injuries. Methods: Study Design: Prospective, randomized, controlled animal study. Sprague-Dawley rats were randomly divided into three groups: intracranial sham surgery or intracranial crush injury with or without ES and TP treatments. The intracranial sham group underwent exposure of the meatal segment of the right facial nerve. The intracranial crush groups underwent a crush of the meatal segment following exposure with or without ES and TP treatment immediately following the injury and were followed for 8 weeks. Brain sections were thionin-stained, and facial motoneurons were counted using light microscopy. Results were compared to intratemporal and extracranial facial nerve crush injuries. Results: Intracranial crush injury resulted in a significant decrease in cell survival of 65.6% as compared to the sham group (99.4%). The treatments increased cell survival to 93.8%. The cell loss in the intracranial facial nerve injury is more substantial than the intratemporal (85.8%) and extracranial (103.3%) injuries. Conclusions: Intracranial injury results in a more profound cell loss compared to the distal injuries; however, combinatory treatments improve facial motoneuron survivability regardless of injury location. These data suggest the important clinical implication that this combinatorial treatment may significantly improve cell survival and therefore facial nerve function following even the most severe facial nerve injuries.

Inner Ear Effects of Canal Wall Down Mastoidectomy: A Prospective Study

Objective: Evaluate the inner ear effects of canal wall down (CWD) mastoidectomy in the treatment of chronic otitis media (COM) in regard to bone conduction hearing and reported tinnitus and dizziness related disability. Method: Prospective study of 86 consecutive patients treated by CWD mastoidectomy for COM with or without cholesteatoma. Patients underwent preoperative audiogram and completion of 2 surveys: Dizziness Handicap Inventory (DHI) and Tinnitus Handicap Inventory (THI), which were repeated 4 to 6 months postoperatively. Results: No significant change in bone-conduction hearing scores occurred postoperatively. DHI and THI scores improved in the vast majority of patients. Thirteen patients, 13 out of 34 (38%), had DHI improvement greater than 18 points, indicating a significant patient-perceived improvement in dizziness-related disability. Sixteen patients, 16 out of 43 (37%), had THI improvement greater than 20 points, indicating a significant patient-perceived improvement in tinnitus-related disability. Three patients developed new-onset postoperative dizziness, and 5 patients developed new-onset postoperative tinnitus. The odds ratio for improving DHI and THI scores relative to or worsening scores is 6.6 in DHI (95% CI: 1.8 to 25.0) and 4.2 in THI (95% CI: 1.45 to 12.2). Conclusion: Canal wall down mastoidectomy did not result in new-onset sensorineural hearing loss. In addition, using the Dizziness Handicap Inventory and Tinnitus Handicap Inventory measures, patient-perceived disability from dizziness and tinnitus was shown to decrease after mastoid surgery.