Faculty Bibliography

Bone morphogenetic protein (BMP) has been reported to cause early inflammatory changes, ectopic bony formation, adjacent level fusion, radiculitis, and osteolysis. The authors describe the case of a patient who developed inflammatory fibroblastic cyst formation around the BMP sponge after a lumbar fusion, resulting in compressive lumbar radiculopathy. A 70-year-old woman presented with left L-4 and L-5 radiculopathy caused by a Grade I spondylolisthesis with a left herniated disc at L4-5. She underwent a minimally invasive transforaminal lumbar interbody fusion with BMP packed into the interbody cage at L4-5. Her neurological symptoms resolved immediately postoperatively. Six weeks later, the patient developed recurrence of radiculopathy. Radiological imaging demonstrated an intraspinal cyst with a fluid-fluid level causing compression of the left L-4 and L-5 nerve roots. Reexpoloration of the fusion was performed, and a cyst arising from the posterior aspect of the cage was found to compress the axilla of the left L-4 nerve root and the shoulder of the L-5 nerve root. The cyst was decompressed, and the wall was partially excised. A collagen BMP sponge was found within the cyst and was removed. Postoperatively, the patient's radiculopathy resolved and she went on to achieve interbody fusion. Bone morphogenetic protein can be associated with inflammatory cyst formation resulting in neural compression. Spine surgeons should be aware of this complication in addition to the other reported BMP-related complications.

OBJECTIVE: We compared the incidence of postoperative cerebrospinal fluid (CSF) leaks in patients undergoing endoscopic skull base repair with a pedicled nasoseptal flap (PNSF) with or without the addition of a dural sealant. STUDY DESIGN AND SETTING: Retrospective analysis at a tertiary care medical center. METHODS: A retrospective analysis was performed at our tertiary care medical center on patients who underwent endoscopic repair of high-flow CSF leaks using a PNSF between December 2008 and August 2011. Repair materials, incidence of postoperative CSF leaks, and demographic data were collected. RESULTS: Thirty-two high-flow CSF leaks were repaired with a PNSF alone without dural sealant (group A), and 42 were repaired with a PNSF with the addition of a dural sealant (group B). In group A, there were no postoperative CSF leaks (0%), whereas in group B, there was 1 delayed postoperative CSF leak, resulting in a 2.4% leak rate. The incidence of postoperative CSF leakage was not significantly different between the 2 groups (P = .38). The overall postoperative CSF leak rate was 1.4%. CONCLUSIONS: The use of dural sealants when performing endoscopic PNSF repair of high-flow CSF leaks is not supported by our data. In addition, this practice may significantly increase surgical cost. We encountered no postoperative CSF leaks in patients with high-flow CSF leaks treated with PNSF alone without dural sealants. Meticulous surgical technique and proper positioning of the PNSF seem to obviate the need for dural sealants during endoscopic skull base reconstruction of high-flow CSF leaks.

OBJECTIVES/HYPOTHESIS: The development of expanded endoscopic endonasal approaches (EEAs) has allowed resection of cranial-base lesions beyond the sella. One major criticism is an increased risk of postoperative cerebrospinal fluid (CSF) leakage because of the larger skull base defect. We evaluated our experience with vascularized pedicled nasoseptal flap (PNSF) reconstruction and compared the postoperative CSF leak rates between patients undergoing endoscopic transsphenoidal (transsellar) approaches versus expanded EEA (transplanum-transtuberculum, transcribriform, transclival). STUDY DESIGN: Retrospective analysis at a tertiary care medical center. METHODS: A retrospective review of a prospective database was performed on patients who underwent PNSF reconstruction for intraoperative high-flow CSF leaks after EEA between December 2008 and August 2011. Demographic data, repair materials, surgical approach, and incidence of postoperative CSF leaks were collected. RESULTS: Thirty-seven transsellar defects (group I) were repaired with a PNSF, and 32 expanded EEA defects (19 transplanum-transtuberculum, 10 transcribriform, three transclival) (group II) were repaired with a PNSF. No postoperative CSF leaks occurred in group I. One delayed postoperative CSF leak was encountered in group II leading to a 3.1% leak rate in that group. The incidence of postoperative CSF leakage was not significantly different between the two groups (P > .05). Our overall success rate in this series using a PNSF was 98.6%. CONCLUSIONS: Based on our data, there is no significant increased risk of postoperative CSF leak between transsellar and expanded EEA defects when a PNSF is used. The potential risk of postoperative CSF leaks associated with larger defects created through expanded EEA can be minimized by multilayered closure with a PNSF and meticulous surgical technique.

BACKGROUND: The advances in endoscopic skull base surgery have led to the resection of increasingly larger cranial base lesions and the creation of larger skull base defects with the potential for increased postoperative high-flow cerebrospinal fluid (CSF) leaks. These concerns led to the development of the vascularized pedicled nasoseptal flap (PNSF), which is now used as the mainstay for repair of large skull base defects in many academic centers. In this report, we review the incidence of postoperative CSF leaks in our institution in patients undergoing endoscopic skull base repair of high-flow CSF leaks with a vascularized PNSF without concurrent CSF diversion. METHODS: We performed a retrospective analysis at our tertiary care medical center on patients who underwent endoscopic repair of high-flow CSF leaks using a PNSF without CSF diversion between July 2008 and August 2011. Repair materials, incidence of postoperative CSF leaks, and demographic data were collected. RESULTS: Fifty-nine high-flow CSF leaks were repaired with a PNSF and other repair materials, without the use of lumbar catheter drainage. No postoperative CSF leak occurred in this cohort of patients. The overall postoperative CSF leak rate was 0%. CONCLUSION: Meticulous multilayer-closure of skull base defects is critical to prevent postoperative CSF leaks. Although lumbar drainage may be useful in select scenarios, it carries inherent risks of intracranial hypotension and pneumocephalus, and may not be necessary for routine management of high-flow CSF leaks in conjunction with a robust PNSF. Further prospective randomized controlled studies may be warranted to evaluate the efficacy of postoperative lumbar drainage.

Lateral sphenoid encephaloceles of the Sternberg canal are rare entities and usually present with spontaneous CSF rhinorrhea. Traditionally, these were treated via transcranial approaches, which can be challenging given the deep location of these lesions. However, with advancements in endoscopic skull base surgery, including improved surgical exposures, angled endoscopes and instruments, and novel repair techniques, these encephaloceles can be resected and successfully repaired with purely endoscopic endonasal approaches. In this report, the authors review the endoscopic endonasal transpterygoid approach to the lateral recess of the sphenoid sinus for repair of temporal lobe encephaloceles, including an overview of the surgical anatomy from an endoscopic perspective, and describe the technical operative nuances and surgical pearls for these cases. The authors also present 4 new cases of lateral sphenoid recess encephaloceles that were successfully treated using this approach.

Extended endoscopic endonasal approaches have allowed for a minimally invasive solution for removal of a variety of ventral skull base lesions, including intradural tumors. Depending on the location of the pathological entity, various types of surgical corridors are used, such as transcribriform, transplanum transtuberculum, transsellar, transclival, and transodontoid approaches. Often, a large skull base dural defect with a high-flow CSF leak is created after endoscopic skull base surgery. Successful reconstruction of the cranial base defect is paramount to separate the intracranial contents from the paranasal sinus contents and to prevent postoperative CSF leakage. The vascularized pedicled nasoseptal flap (PNSF) has become the workhorse for cranial base reconstruction after endoscopic skull base surgery, dramatically reducing the rate of postoperative CSF leakage since its implementation. In this report, the authors review the surgical technique and describe the operative nuances and lessons learned for successful multilayered PNSF reconstruction of cranial base defects with high-flow CSF leaks created after endoscopic skull base surgery. The authors specifically highlight important surgical pearls that are critical for successful PNSF reconstruction, including target-specific flap design and harvesting, pedicle preservation, preparation of bony defect and graft site to optimize flap adherence, multilayered closure technique, maximization of the reach of the flap, final flap positioning, and proper bolstering and buttressing of the PNSF to prevent flap dehiscence. Using this technique in 93 patients, the authors' overall postoperative CSF leak rate was 3.2%. An illustrative intraoperative video demonstrating the reconstruction technique is also presented.

OBJECTIVES/HYPOTHESIS: Numerous professional societies, clinical practices, and hospitals provide Internet-based patient education materials (PEMs) to the general public, but not all of this information is written at a reading level appropriate for the average patient. The National Institutes of Health and the US Department of Health and Human Services recommend that PEMs be written at or below the sixth-grade level. Our purpose was to assess the readability of endoscopic sinus surgery (ESS)-related PEMs available on the Internet and compare readability levels of PEMs provided by three sources: professional societies, clinical practices, and hospitals. STUDY DESIGN: A descriptive and correlational design was used for this study. METHODS: The readability of 31 ESS-related PEMs was assessed with four different readability indices: Flesch-Kincaid Grade Level (FKGL), Flesch Reading Ease Score (FRES), Simple Measure of Gobbledygook (SMOG), and Gunning Frequency of Gobbledygook (Gunning FOG). Averages were evaluated against national recommendations and between each source using analysis of variance and t tests. RESULTS: The majority of PEMs (96.8%) were written above the recommended sixth-grade reading level, based on FKGL (P < .001). Only one article (3.2%) had an FKGL at or below the sixth-grade level. The mean readability values were: FRES 47.1 +/- 13.4, FKGL 10.7 +/- 2.4, SMOG 13.7 +/- 1.6, and Gunning FOG 12.4 +/- 2.7. CONCLUSIONS: Current Internet-based PEMs related to ESS, regardless of source type, were written well above the recommended sixth-grade level. Materials from the hospitals/university-affiliated websites had lower readability scores, but were still above recommended levels. Web-based PEMs pertaining to ESS should be written with the average patient in mind.

With the relatively recent increase in the use of MRI techniques, there has been a concurrent rise in the number of vestibular schwannomas (VSs) detected as incidental findings. These incidental VSs may be prevalent in up to 0.02%-0.07% of individuals undergoing MRI and represent a significant portion of all diagnosed VSs. The management of these lesions poses a significant challenge for practitioners. Most incidental VSs tend to be small and associated with minimal symptoms, permitting them to be managed conservatively at the time of diagnosis. However, relatively few indicators consistently predict tumor growth and patient outcomes. Furthermore, growth rates have been shown to vary significantly over time with a large variety of long-term growth patterns. Thus, early MRI screening for continued tumor growth followed by repeated MRI studies and clinical assessments throughout the patient's life is an essential component in a conservative management strategy. Note that tumor growth is typically associated with a worsening of symptoms in patients who undergo conservative management, and many of these symptoms have been shown to significantly impact the patient's quality of life. Specific indications for the termination of conservative management vary across studies, but secondary intervention has been shown to be a relatively safe option in most patients with progressive disease. Patients with incidental VSs will probably qualify for a course of conservative management at diagnosis, and regular imaging combined with the expectation that the tumor and symptoms may change at any interval is crucial to ensuring positive long-term outcomes in these patients. In this report, the authors discuss the current literature pertaining to the prevalence of incidental VSs and various considerations in the management of these lesions. It is hoped that by incorporating an understanding of tumor growth, patient outcomes, and management strategies, practitioners will be able to effectively address this challenging disease entity.

OBJECTIVE: Fractures of the hyoid bone are rare occurrences. They are mainly caused by strangulation/asphyxiation injuries, trauma to the neck, and motor vehicle accidents (MVAs). As a result of their rarity, proper treatment guidelines are not in place for dealing with these injuries. In this study, a systematic literature review was conducted with the goal of identifying optimal management for patients with fracture of the hyoid bone. DATA SOURCES: MEDLINE and PubMed databases. REVIEW METHODS: The MEDLINE and PubMed databases were searched for patients diagnosed with hyoid bone fracture. Further cases were obtained from the bibliographies of relevant articles. Full-text articles were obtained. Patient presentation, method of diagnosis, treatment regimen, and outcomes are discussed. RESULTS: Forty-six cases were collected from 36 articles. No randomized controlled trials regarding treatment of hyoid fractures were found. The most common etiologies were MVA, assault, and neck trauma during athletic activities. Most common presenting symptoms included dysphagia, odynophagia, and pain upon neck rotation. Most frequent presenting signs included anterior neck tenderness and swelling. Five cases out of 46 had surgical repair of the fractured hyoid bone. In the remaining 41 cases, 26 were treated with conservative management, which included rest/observation, diet changes, and analgesia, while the other 15 cases required tracheotomy or surgical treatment for related injuries. All patients survived and had excellent outcomes with resolution of symptoms. CONCLUSION: This review shows that direct surgical treatment of hyoid fractures was performed in only 10.9% of cases. Both conservative and surgical management yielded positive outcomes.