M. Akkari

Semiautomatic Cochleostomy Target and Insertion Trajectory Planning for Minimally Invasive Cochlear Implantation

A major component of minimally invasive cochlear implantation is atraumatic scala tympani (ST) placement of the electrode array. This work reports on a semiautomatic planning paradigm that uses anatomical landmarks and cochlear surface models for cochleostomy target and insertion trajectory computation. The method was validated in a human whole head cadaver model (n = 10 ears). Cochleostomy targets were generated from an automated script and used for consecutive planning of a direct cochlear access (DCA) drill trajectory from the mastoid surface to the inner ear. An image-guided robotic system was used to perform both, DCA and cochleostomy drilling. Nine of 10 implanted specimens showed complete ST placement. One case of scala vestibuli insertion occurred due to a registration/drilling error of 0.79 mm. The presented approach indicates that a safe cochleostomy target and insertion trajectory can be planned using conventional clinical imaging modalities, which lack sufficient resolution to identify the basilar membrane.

Atypical presentations of sinonasal inverted papilloma: Surgical management and influence on the recurrence rate.

Background Sinonasal inverted papilloma (SNIP), classically, is a unilateral benign tumor of the nasal lateral wall. Numerous variations have been observed, depending on location, bilateral presentation, or association with nasal polyposis. Objective The aim of this work was to describe atypical presentations of SNIPs with their management specificities and to assess their influence on the recurrence rate in a large case series. Methods A retrospective single center study of 110 patients treated for SNIP. Atypical inverted papillomas were identified according to the following criteria: (1) unusual location (frontal, posterior, anterior), (2) bilateral involvement, and (3) association with nasal polyposis. Surgical management was detailed, and the influence of each atypical group on recurrence was assessed by using Kaplan-Meier survival curves and the log-rank test. Results Distribution of atypical presentations was as follows: frontal sinus localization (10.9%); posterior localization, including sphenoid sinus (9%); nasal anterior localization (3.6%); bilateral involvement (3.6%); and nasal polyposis association (10%). The surgical approach was endoscopic (74.5%), external (5.5%), or combined endoscopic and external (20%). Except for nasal anterior localization, all the groups were associated with a higher recurrence rate, without reaching statistical significance. Conclusion Recurrence rates for these atypical presentations arise from their specific surgical challenges. The choice of the surgical technique is guided by tumor location and extension, and by the surgeons experience; the main objective is a complete resection. The endoscopic endonasal approach is the most frequent procedure.

Manual Electrode Array Insertion Through a Robot-Assisted Minimal Invasive Cochleostomy: Feasibility and Comparison of Two Different Electrode Array Subtypes.

Hypothesis To evaluate the feasibility and the results of insertion of two types of electrode arrays in a robotically assisted surgical approach. Background Recent publications demonstrated that robot-assisted surgery allows the implantation of free-fitting electrode arrays through a cochleostomy drilled via a narrow bony tunnel (DCA). We investigated if electrode arrays from different manufacturers could be used with this approach. Methods Cone-beam CT imaging was performed on fivecadaveric heads after placement of fiducial screws. Relevant anatomical structures were segmented and the DCA trajectory, including the position of the cochleostomy, was defined to target the center of the scala tympani while reducing the risk of lesions to the facial nerve. Med-El Flex 28 and Cochlear CI422 electrodes were implanted on both sides, and their position was verified by cone-beam CT. Finally, temporal bones were dissected to assess the occurrence of damage to anatomical structures during DCA drilling. Results The cochleostomy site was directed in the scala tympani in 9 of 10 cases. The insertion of electrode arrays was successful in 19 of 20 attempts. No facial nerve damage was observed. The average difference between the planned and the postoperative trajectory was 0.17 ± 0.19 mm at the level of the facial nerve. The average depth of insertion was 305.5 ± 55.2 and 243 ± 32.1 degrees with Med-El and Cochlear arrays, respectively. Conclusions Robot-assisted surgery is a reliable tool to allow cochlear implantation through a cochleostomy. Technical solutions must be developed to improve the electrode array insertion using this approach.

Modeling of Auditory Neuron Response Thresholds with Cochlear Implants

The quality of the prosthetic-neural interface is a critical point for cochlear implant efficiency. It depends not only on technical and anatomical factors such as electrode position into the cochlea (depth and scalar placement), electrode impedance, and distance between the electrode and the stimulated auditory neurons, but also on the number of functional auditory neurons. The efficiency of electrical stimulation can be assessed by the measurement of e-CAP in cochlear implant users. In the present study, we modeled the activation of auditory neurons in cochlear implant recipients (nucleus device). The electrical response, measured using auto-NRT (neural responses telemetry) algorithm, has been analyzed using multivariate regression with cubic splines in order to take into account the variations of insertion depth of electrodes amongst subjects as well as the other technical and anatomical factors listed above. NRT thresholds depend on the electrode squared impedance (β = −0.11 ± 0.02, P < 0.01), the scalar placement of the electrodes (β = −8.50 ± 1.97, P < 0.01), and the depth of insertion calculated as the characteristic frequency of auditory neurons (CNF). Distribution of NRT residues according to CNF could provide a proxy of auditory neurons functioning in implanted cochleas.

Comparison of early hearing outcomes of type 2 ossiculoplasty using hydroxyapatite bone cement versus other materials.

OBJECTIVES To compare the hearing outcomes of type 2 ossiculoplasties for erosion of the long process of the incus according to the reconstruction material used: cartilage, ossicles, hydroxyapatite (HAP) partial ossiculoplasty reconstruction prostheses (PORP), titanium PORP, and HAP cement. Complications related to cement reconstruction were systematically investigated and reported. MATERIAL AND METHODS Seventy patients operated between 2007 and 2011 for non-cholesteatomatous chronic otitis media were included in this study. Mean air-bone gap (500, 1000, 2000 and 4000Hz) was compared preoperatively and 3 months postoperatively according to the reconstruction material used. Postoperative results were classified as good (air-bone gap<10dB), acceptable (air-bone gap 10-20dB) or insufficient (air-bone gap>20dB) and were compared according to the reconstruction material used. RESULTS Groups were comparable in terms of preoperative air-bone gap (P>0.05, Anova). The mean postoperative air-bone gap was 14.82±11.52dB in the cartilage group, 13.31±9.03dB in the ossicles group, 22.12±11.95dB in the HAP PORP group, 13.75±11.20dB in the titanium PORP group, and 7.26±8.99dB in the HAP cement group. Statistical analysis showed a significant air-bone gap difference only between HAP PORP and HAP cement groups (P=0.021, Tukeys test). No significant difference was observed between groups when classified by air-bone gap class (P=0.29, Fishers test). No major complication was reported with HAP cement with a minimum follow-up of 10 months. CONCLUSION HAP cement provides similar hearing outcomes to autologous material and titanium PORP, and better outcomes than HAP PORP in our patients. These results must be confirmed in a larger series with a longer follow-up.

Nodular recurrence and hypothyroidism following partial thyroidectomy for benign nodular thyroid disease in children and adolescents

OBJECTIVES Diagnostic and therapeutic processing of a thyroid nodule in children and adolescents may require lobectomy-isthmusectomy (LI) or nodule-resection (NR). Very few data in the literature report the long-term evolution of the remaining thyroid lobe in a defined pediatric population. In this study, we aimed to answer the following questions: Does a nodule recurrence occur in the remainder lobe? Is a post-operative thyroxine treatment necessary? MATERIAL AND METHODS This retrospective study describes 28 patients under 18 who underwent LI (22 cases) or NR (6 cases) from January 2004 to March 2012. Ten of them were lost to follow up, 18 could be assessed (4 NR (22%) and 14 LI (78%) - mean follow-up 45±31 months). All patients benefited of post-operative thyroid ultrasonography, and regular endocrinologic follow-up. The following data were analysed: emergence of new thyroid nodules, evolution of pre-existing nodules, occurrence of post-operative hypothyroidism and requirement for completion thyroidectomy. RESULTS The mean age at the time of surgery was 14.3±1.9 years. Two patients (11%) had pre-existing nodules in the remaining thyroid gland, none of which showed an increase in size after surgery. De novo nodules developed in five patients (27.8%). Three patients who underwent LI (21.4%) needed thyroxine treatment for post-operative hypothyroidism. One patient (5.5%) needed completion thyroidectomy. CONCLUSIONS In this children and adolescents population, after performing LI or NR, remaining thyroid tissue stays free of nodules in 72.2% of the cases. A post-operative thyroxin treatment is necessary in 21.4% of cases after LI.

Thyroid surgery in children and adolescents: a series of 65 cases.

OBJECTIVES To describe the specificities and complications of thyroid surgery in children and adolescents. MATERIAL AND METHODS This retrospective study was based on 64 patients under the age of 18 who underwent thyroid surgery between January 2004 and March 2012, with two operations in one case. The following data were analysed: anatomical variants of the recurrent laryngeal nerve, postoperative recurrent laryngeal nerve paralysis rate, postoperative hypoparathyroidism rate, and histological results. RESULTS Two cases of right non-recurrent inferior laryngeal nerve were observed (2.2% of the 93 recurrent laryngeal nerves dissected). One case of persistent left recurrent laryngeal nerve paralysis was observed (1.1%) despite intraoperative recurrent laryngeal nerve monitoring. Eight cases of immediate postoperative hypocalcaemia were observed (23.5% of the 34 total thyroidectomies) and permanent hypocalcaemia was observed in 5 cases (14.7%) with a significantly lower immediate postoperative serum calcium than in the case of transient hypocalcaemia (P=0.035). Among the 11 patients operated for familial medullary thyroid carcinoma (MTC), 36.3% presented one or more sites of C-cell carcinoma. Among the 32 patients operated for thyroid nodule, 6.3% presented papillary adenocarcinoma. Histological results were benign in all other cases. CONCLUSIONS Thyroid surgery in children and adolescents is part of global multidisciplinary management of thyroid disorders in children. Recurrent laryngeal nerve paralysis is a rare complication, but may occur despite the use of intraoperative recurrent laryngeal nerve monitoring. Permanent hypoparathyroidism is the most common complication and is correlated with immediate postoperative serum calcium. Systematic prophylactic total thyroidectomy in patients with a RET proto-oncogene mutation allowed early diagnosis of MTC in one-third of cases. In view of the low rate of malignant nodules in our series, the malignant thyroid nodule rates reported in children in the literature may be overestimated.

Endovascular management of a carotid aneurysm into the sphenoid sinus presenting with epistaxis.

Non-traumatic cavernous internal carotid artery (ICA) aneurysms are rare, and favour the occurrence of massive recurrent epistaxis, which is associated with a high mortality rate. We report the case of a 67-year-old woman presenting a ruptured ICA aneurysm extending into the sphenoid sinus, revealed by epistaxis. Selective coil embolization of the aneurysm was performed. Flow-diverter stents were deployed in order to utterly exclude the aneurysm and prevent revascularization. Anti-platelet treatment was provided to lower the risk of in-stent thrombosis. A left frontal hematoma associated with a subarachnoid haemorrhage occurred at day 2. Outcome was favourable with no neurological sequelae, and no clinical recurrence of epistaxis occurred. A 4 months follow-up digital subtraction angiography showed a complete exclusion of the aneurysm. In addition, a magnetic resonance cerebral angiography at 16 months showed stable results. Thus, this two-stage endovascular procedure has proven its effectiveness in preventing epistaxis recurrence while preserving the ICA patency.

Sphenoidal sinogenic extradural empyema associated with juvenile myelomonocytic leukemia

Intracranial empyema is a rare but serious complication of sinusitis in children. Myelodysplastic/myeloproliferative syndromes (MMS), including juvenile myelomonocytic leukemia (JMML), can lead to immunosuppression, thus favouring infections. We report the case of a sphenoid sinogenic retro-clival extradural empyema in a 14-year-old female patient associated with JMML. Treatment consisted in an endonasal transphenoidal drainage of the empyema associated with intravenous antibiotherapy. The patient was thereafter enrolled in chemotherapeutic treatment with Azacitidine. The disease progressed to blast phase, indicating bone marrow graft. This is the first reported case of an endocranial complication of bacterial sinusitis associated with MMS in a child.

Evaluation of otoscopy simulation as a training tool for real-time remote otoscopy

Abstract Objective: Teleotoscopy requires the assistance of telehealth facilitators; but their training requirements remain to be determined. We evaluated the use of an otoscopy simulator to train facilitators to remote otoscopies sent via the Internet using a teleaudiology platform. Design: Neurotologists experts were asked to identify images using the otoscopy simulator and to perform an identification task of significant anatomical landmarks. The experts were asked to repeat those tasks remotely, with the help of facilitators who either received basic training, or no training prior to the experiment. Study sample: Three experts, three trained facilitators and three untrained facilitators participated in this study. Results: The use of an otoscopy simulator in addition to remote otoscopy yielded a good inter- and intrarater agreement (κ between 0.81–1, and 0.80–0.87, respectively). The accuracy of diagnosis was high on-site (11.7% error) and remotely (0% error). The time required for landmark identification task was not increased when performed remotely with a trained facilitator versus on-site otoscopy (9.3 versus 9.2 s/landmark). Conversely, the lack of training of facilitators increased significantly this time (15.6 s/landmark, p < 0.001). Conclusion: An otoscopic simulator coupled to teleaudiology software can be used to efficiently train both experts and facilitators to perform remote otoscopy.