Anatomic comparison of nasal versus lateral surgical access to the petrous apex.

To compare anatomic access to the petrous apex via the nasal and lateral approaches. Hundred consecutive fine-cut CT temporal bones at the Royal Melbourne Hospital from July 27, 2007 to October 30, 2010 were reviewed. Easy lateral access allowed use of a 4 mm burr past vital structures. Easy nasal access was defined as sphenoid pneumatization to/beyond the posterior sella and laterally beyond the maxillary/vidian nerves. Three patients with petrous apex pathology were also reviewed. Easy lateral and nasal access occurred in 74 (37%) and 79 (39.5%) sides, respectively. Easy nasal and lateral access were not strongly correlated (r = 0.10, P = 0.15). A well-pneumatized mastoid (62.5%) was strongly correlated with a large sphenoid (63%, P < 0.001). Pneumatization of the mastoid corresponds to sphenoid sinus size. However, surgical access to the petrous apex is more determined by proximity of vital structures. Easy surgical access via the nasal or lateral approaches was not strongly correlated. Petrous apex lesions requiring surgery should be considered for both approaches.

Surgery for neurofibromatosis 2.

PURPOSE OF REVIEW: This study reviews the latest literature relating to the surgical treatment of otologic manifestations in patients with neurofibromatosis 2 (NF2). The emphasis is on vestibular and other schwannomas. We review surgical approaches, including hearing preservation and nonhearing preservation surgery, as well as outcomes, including hearing and facial nerve function. RECENT FINDINGS: Vestibular schwannomas in NF2 are difficult to manage because they are bilateral and may be aggressive. Depending on hearing status, tumor size and the presence or absence of compressive symptoms, these tumors can be managed by observation, radiotherapy or surgery. The goal is to maximize the years of useful hearing. Surgery may attempt to preserve hearing or aim for complete tumor resection and preservation of facial nerve function. SUMMARY: The natural history of vestibular schwannomas and other tumors in patients with NF2 is difficult to predict. The decision between observation and either medical or surgical intervention, as well as the choice of surgical procedure, depend on patient factors and preferences and on the experience of the treating center.

Analysis of hearing preservation after endolymphatic mastoid sac surgery for Meniere's disease.

OBJECTIVES/HYPOTHESIS: Comparison of audiometric outcomes between patients with definite Meniere's disease who underwent endolymphatic mastoid sac surgery (EMSS) following failed medical therapy and patients who underwent medical therapy only. STUDY DESIGN: Retrospective chart review of 456 consecutive patients between 1997 and 2006. METHODS: Outcome measures were changes in pure-tone average (PTA), word recognition score (WRS), and speech reception threshold (SRT). RESULTS: Of 58 qualified patients, 29 who underwent EMSS after failing medical therapy showed a 4 dB decrease in PTA, a 2% increase in WRS, and a 2 dB decrease in SRT. Twenty-nine patients treated with medical therapy only demonstrated a 1 dB PTA increase, 2% WRS improvement, and 2 dB SRT improvement. No significant difference was noted between the medically and surgically managed patients in terms of changes in PTA (P = .34) or WRS (P = .95) after treatment. Of all patients in the study, 60% had no clinically significant change in hearing, whereas 24% improved and 16% worsened. The distribution of post-treatment hearing changes between the medical and surgical groups was statistically insignificant (P = .17). CONCLUSIONS: The changes in PTA and WRS among patients with Meniere's disease managed with medical therapy or EMSS were not statistically significant. Although performing EMSS to treat the vertigo of Meniere's disease does not appear to be associated with an increased risk of deteriorating auditory function after treatment, surgery also does not confer an increased likelihood of stabilizing or improving hearing.

Radiographic anatomy of the infracochlear approach to the petrous apex for computer-assisted surgery.

OBJECTIVE: 1) To define the surgical anatomy and dimensions of the infracochlear approach to the petrous apex through the use of high-resolution computed tomography and 2) use of digitized images of cadaveric temporal bones for computer simulation of infracochlear access using the Ohio Supercomputer Center/Ohio State University temporal bone simulator. BACKGROUND: The petrous apex is a surgically challenging area to access. Many routes have been described and used successfully in clinical practice. However, these routes have not been defined with the aim of application in computer-assisted surgery. The infracochlear approach, due to its access via a transcanal route, affords the opportunity for its potential application in minimally invasive computer-assisted surgery. METHODS: High-resolution computed tomographic scans were performed on 102 cadaveric skulls (204 temporal bones). Standard measurements were taken using an open-source picture archiving and communication system software of the maximum height, width, and depth of the infracochlear approach. In addition, the maximum diameter of a circular fenestration that could be created in the infracochlear space without breaching the basal turn of the cochlea, internal carotid artery, or the jugular bulb was used to simulate a drill path. In addition, 5 temporal bone specimens (3 left, 2 right) underwent high-resolution computed tomography, with the digitized images being used to create simulated temporal bones for infracochlear surgical access; the transcanal infracochlear approach was then performed by the same surgeon on the cadaveric bone. RESULTS: The mean height, width, and depth of the infracochlear space in temporal bones with nonpneumatized petrous apices were 7.2 +/- 0.4, 9.4 +/- 0.8, and 17.5 +/- 1.0 mm, respectively. Corresponding dimensions in pneumatized petrous apices were 7.6 +/- 0.4, 10.1 +/- 1.1, and 18.6 +/- 0.8 mm, respectively. The mean diameter of the circular fenestra in the nonpneumatized petrous apices was 5.1 +/- 0.4 compared with 5.7 +/- 0.6 mm in pneumatized petrous pieces. This was statistically significant (unpaired t test; p value = 0.04). The time to perform a simulated infracochlear approach to the petrous apex ranged from 3.1 to 12.6 minutes (mean, 6.1 minutes). The time to perform the same approach on the cadaveric bone ranged from 4.32 to 14.1 minutes (mean, 9.3 minutes). CONCLUSION: Temporal bones with pneumatized petrous apices have an overall larger infracochlear space. The mean diameter of a circular infracochlear path that would avoid damage to vital structures was sufficiently large in both pneumatized and nonpneumatized petrous apices to have a potential application as a safe approach in computer-assisted surgery. Such an application is feasible with mating of a robotic system with computed tomographic- or magnetic resonance imaging-guided imagery, which is the next phase of this study.

The enigmatic trigeminal caroticodural fold: an anatomic description and surgical relevance to anterior petrosectomy.

OBJECTIVES/HYPOTHESIS: We describe our cadaveric dissections and clinical findings that address anterior and ventral limitations imposed by the trigeminal nerve. Particularly, we identify the trigeminal caroticodural fold, the vestment of dura that traverses the space between the nerve and the internal carotid artery. We address the effect of mobilization of this fold to optimize access in Kawase's space when approaching the clivus and posterior fossa. METHODS: Histological study and cadaveric dissections were performed to examine this regional anatomy. Our clinical series (2002 to 2007) includes 30 patients who underwent anterior petrosectomy as part of more complex approaches for lesions of the skull base. RESULTS: Histological and dissection specimens showed a dense fibrous confluence lateral to the trigeminal ganglion and portions of the trigeminal nerve that we called the trigeminal caroticodural fold. This fold was prominent in 18 patients, ill-defined in six, and absent in six patients. Incision of the trigeminal caroticodural fold permitted between 1 mm and 3 mm of additional exposure for drilling in Kawase's space without direct trauma to V(3). CONCLUSIONS: Our study highlights the existence of a dural tethering of the trigeminal nerve and ganglion relevant to surgical exposure of Kawase's space. The regional dural anatomy that contributes to the trigeminal caroticodural fold is complex with subtle variances. We suggest that identification of this fold and its sharp dissection allows mobilization of the trigeminal ganglion and nerve without violation of V(3), and ultimately can improve the transpetrosal access to the upper clivus and posterior fossa via this corridor. Laryngoscope, 2009.

Indications for and outcomes of mastoid obliteration in cochlear implantation.

OBJECTIVE: To review the indications, efficacy, and long-term outcomes of mastoid obliteration in cochlear implant surgery. STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: Seventeen patients who underwent a mastoid obliteration procedure to facilitate the insertion of a cochlear implant between 1978 and 2005. INTERVENTION: Mastoid obliteration procedure before cochlear implantation. MAIN OUTCOME MEASURES: Revision rate of the mastoid obliteration and cochlear implantation, postoperative audiometric scores (consonant-nucleus-consonant words/phonemes, Central Institute for the Deaf sentences, City University New York sentences in quiet and in noise), and incidence of complications. RESULTS: There were 17 patients with a median age of 60 years (range, 3-79 yr). Eight patients required mastoid obliteration for active chronic suppurative otitis media before cochlear implantation. Another 8 patients had existing mastoid cavities requiring obliteration (modified radical [n = 5] and fenestration cavities [n = 3]). A single patient with a sclerotic mastoid and an anterior sigmoid sinus underwent obliteration because of inadequate surgical access. The technique of obliteration was radical mastoidectomy with eustachian tube occlusion, blind sac closure of the external auditory canal, and cavity obliteration with either temporalis muscle flap (n = 15) or abdominal fat (n = 2). Cochlear implantation and mastoid obliteration were performed as a two-stage procedure in 10 patients and as a single-stage procedure in 7. Two patients required revision of the mastoid obliteration. At follow-up, all patients had stable obliterated cavities. Fifteen patients obtained significant improvement in speech discrimination scores, whereas 2 patients obtained some benefit from the cochlear implant through the perception of environmental sounds. CONCLUSION: For patients with chronic suppurative otitis media or existing mastoid cavities, the obliteration with temporalis muscle or abdominal fat is an effective technique to facilitate safe cochlear implantation.

Incidence of severe acquired subglottic stenosis in newborns.

OBJECTIVE: To determine the change in the statewide incidence of severe acquired subglottic stenosis (SGS) in newborns over the past decade. METHODS: Multicenter, statewide retrospective study of all patients under the age of 12 months who were diagnosed with acquired SGS that required surgical intervention by anterior cricoid split (ACS) or tracheostomy between 1993 and 2003. RESULTS: There were 34 patients (19 male; 15 female) with a median age of 4 months at the time of surgery. The primary surgical intervention performed was ACS 20, and tracheostomy 14 (incidence rate of 41%). Subsequently, 11 patients who failed decannulation following ACS underwent tracheostomy. Five patients died due to reasons unrelated to their SGS, and among the 29 survivors, 8 remain cannulated. The overall success rate for ACS was 35%. The mean annual statewide incidence of severe acquired SGS over the 10-year period was 4.95 per 100,000 live births. CONCLUSION: The annual incidence of acquired SGS in newborns requiring open surgical intervention is in the order of 0.005%. The incidence of acquired SGS provides us with a benchmark figure that reflects the quality and standard of obstetric, neonatal and pediatric care across the state.

Clinical experience with Crohn's disease.

AIM: To determine the clinical spectrum of Crohn's disease in a surgical practice, and to show the safety and efficacy of the range of procedures performed. METHODS: A consecutive series of 92 patients with Crohn's disease who presented between January 1988 and August 2001 to a surgical practice were studied. RESULTS: Ninety two patients (42 male, 50 female), with a mean age of 43 years (range 19-91 years) underwent surgery between January 1998 and August 2001. The mean length of follow up was 46 months (range 1-166 months). Forty patients had disease in more than one site, compared with 52 patients with single site disease. In total, 184 procedures were performed. Patients with the combination of colonic and anorectal disease required more surgical interventions than patients with other disease distributions. At follow up, all patients with disease confined to the small intestine or ileocaecal region were free of symptoms with the only nine taking medication. No patients presenting with colonic disease had symptomatic disease or were taking any anti-inflammatory medication at time of follow up. However, in the group of patients with anorectal or the combination of colonic and anorectal disease, 42% had ongoing symptoms (predominantly anorectal). Fifteen patients had a stoma at some point during their surgical course. CONCLUSION: In a tertiary referral setting, surgical treatment of Crohn's disease can carry a low morbidity with good relief and control of symptoms when used for specific indications. Those with small bowel or colonic disease have better outcomes following surgery compared to those with anorectal disease.