Cochlear and Vestibular Volumes in Inner Ear Malformations.

A "gold standard" for quantitatively diagnosing inner ear malformations (IEMs) and a consensus on normative measurements are lacking. Reference ranges and cutoff values of inner ear dimensions may add in distinguishing IEM types. This study evaluates the volumes of the cochlea and vestibular system in different types of IEM. STUDY DESIGN: Retrospective cohort. SETTING: Tertiary academic center. PATIENTS: High-resolution CT scans of 115 temporal bones (70 with IEM; cochlear hypoplasia [CH]; n = 19), incomplete partition (IP) Types I and III (n = 16), IP Type II with an enlarged vestibular aqueduct (Mondini malformation; n = 16), enlarged vestibular aqueduct syndrome (n = 19), and 45 controls. INTERVENTIONS: Volumetry by software-based, semiautomatic segmentation, and 3D reconstruction. MAIN OUTCOME MEASURES: Differences in volumes among IEM and between IEM types and controls; interrater reliability. RESULTS: Compared with controls (mean volume, 78.0 mm3), only CH showed a significantly different cochlear volume (mean volume, 30.2 mm3; p < 0.0001) among all types of IEM. A cutoff value of 60 mm3 separated 100% of CH cases from controls. Compared with controls, significantly larger vestibular system volumes were found in Mondini malformation (mean difference, 22.9 mm3; p = 0.009) and IP (mean difference, 24.1 mm3; p = 0.005). In contrast, CH showed a significantly smaller vestibular system volume (mean difference, 41.1 mm3; p < 0.0001). A good interrater reliability was found for all three-dimensional measurements (ICC = 0.86-0.91). CONCLUSION: Quantitative reference values for IEM obtained in this study were in line with existing qualitative diagnostic characteristics. A cutoff value less than 60 mm3 may indicate an abnormally small cochlea. Normal reference values for volumes of the cochlea and vestibular system may aid in diagnosing IEM.

A novel method of identifying inner ear malformation types by pattern recognition in the mid modiolar section.

Identification of the inner ear malformation types from radiographs is a complex process. We hypothesize that each inner ear anatomical type has a uniqueness in its appearance in radiographs. The outer contour of the inner ear was captured from the mid-modiolar section, perpendicular to the oblique-coronal plane, from which the A-value was determined from CT scans with different inner ear anatomical types. The mean A-value of normal anatomy (NA) and enlarged vestibular aqueduct syndrome (EVAS) anatomical types was greater than for Incomplete Partition (IP) type I, II, III and cochlear hypoplasia. The outer contour of the cochlear portion within the mid-modiolar section of NA and EVAS resembles the side view of Aladdin's lamp; IP type I resembles the side-view of the Sphinx pyramid and type II a Pomeranian dog's face. The steep spiraling cochlear turns of IP type III resemble an Auger screw tip. Drawing a line parallel to the posterior margin of internal auditory canal (IAC) in axial-view, bisecting the cavity into cochlear and vestibular portions, identifies common-cavity; whereas a cavity that falls under the straight-line leaving no cochlear portion identifies cochlear aplasia. An atlas of the outer contour of seventy-eight inner ears was created for the identification of the inner malformation types precisely.

Evaluating Common Cavity Cochlear Deformities Using CT Images and 3D Reconstruction.

OBJECTIVES: The aim of this study is to compare the common cavity (CC) with the normal anatomy inner ear in order to evaluate whether the cavity is representing both the cochlear and the vestibular parts of the inner ear and to revisit CC deformity from a three-dimensional (3D) perspective. METHODS: High-resolution computed tomography image datasets of 17 temporal bones initially identified as CC were evaluated with 3D reconstruction and multiplanar image analysis using a free available software for 3D segmentation of the inner ear. All 3D images of CC were compared to a normal inner ear. Maximum and minimum diameter of the CC were correlated with the circumference of the CC in an axial plane. RESULTS: In 13 cases (76%), CC represented only the vestibular part of the inner ear and did not represent CC as defined here and by Sennaroglu, Kontorinis, and Khan. True CC was correctly diagnosed in only one case (6%). In three cases (18%), a rudimentary part of the cochlear portion could be identified. The axes' length of the elliptical cavity showed a strong positive linear relation to the circumference of the cavity (long axis: r = 0.94; P < .0001; short axis: r = 0.68; P = .0029). CONCLUSION: This study supports the assumption that many reported CC cases only represent the vestibular part of the inner ear and are therefore cases of cochlear aplasia. 3D segmentation and systematic analysis of CT-imaging add clinical value to the comprehension of the morphology of the anatomical structures of the inner ear. LEVEL OF EVIDENCE: 2C Laryngoscope, 131:386-391, 2021.

A Window Into the Whole Story: Temporal Bone Plasmacytoma Presenting With a Mobile Third Window.

A 63-year-old man presented with imbalance when coughing due to a respiratory tract infection. He had a history of multiple myeloma with a plasmacytoma of the left temporal bone. Examination revealed a positive leftward head impulse test, no spontaneous nystagmus, left-beating positional nystagmus, and left-beating Valsalva-induced nystagmus. Videonystagmography, audiology, and comprehensive vestibular function tests revealed a subtotal left peripheral audio-vestibular loss. Temporal bone computed tomography showed an unchanged bony erosion of the left labyrinth from 2 years prior. Vertigo subsided after treatment of the respiratory tract infection. Although no tumor progression was evident, coughing had triggered a preexisting third mobile window to declare itself. Laryngoscope, 131:E966-E969, 2021.

New Classification of Cochlear Hypoplasia Type Malformation: Relevance in Cochlear Implantation.

OBJECTIVES: This paper attempts to create a new classification type of cochlear hypoplasia (CH)-type malformation taking into consideration of vestibular section and internal auditory canal (IAC). MATERIALS AND METHODS: Preoperative computed-tomography (CT) scans of cochlear implant (CI) candidates (N=31) from various clinics across the world with CH type malformation were taken for analysis. CT dataset were loaded into 3D-slicer freeware for three-dimensional (3D) segmentation of the inner-ear by capturing complete inner-ear structures from the entire dataset. Cochlear size in terms of diameter of available cochlear basal turn and length of cochlear lumen was measured from the dataset. In addition, structural connection between IAC and cochlear portions was scrutinized, which is highly relevant to the proposed CH classification in this study. RESULTS: CH group-I has the normal presence of IAC leading to cochlear and vestibular portions, whereas CH group-II is like CH group-I but with some degree of disruption in vestibular portion. In CH group-III, a disconnection between IAC and the cochlear portion irrespective of other features. Within all these three CH groups, the basal turn diameter varied between 3.1 mm and 9.6 mm, and the corresponding cochlear lumen length varied between 3 mm and 21 mm for the CI electrode array placement. CONCLUSION: A new classification of CH mainly based on the IAC connecting the cochlear and vestibular portions is presented in this study. CI electrode array length could be selected based on the length of the cochlear lumen, which can be observed from the 3D image.

Abnormal cochleovestibular anatomy and imaging: Lack of consistency across quality of images, sequences obtained, and official reports.

OBJECTIVES: There are significant variations across centers on how to acquire and interpret imaging of children with congenital sensorineural hearing loss and cochleovestibular abnormalities. This study assesses the quality of imaging, sequences included, and accuracy of official radiology reports, to determine if these children are being assessed appropriately. METHODS: This study is retrospective review of CTs and MRIs from 40 pediatric patients diagnosed with profound sensorineural hearing loss and cochleovestibular structure/nerve abnormalities presenting to a tertiary referral academic center. Images were reviewed by two experienced neuroradiologists and a neurotologist. Findings were compared to official reports, when available. RESULTS: Twelve (30%) patients had an MRI only, while 28 (70%) had both an MRI and a CT. There were 3 (10.7%) CTs and 7 (17.5%) MRIs noted to be of poor quality. Children received an average of 6.8 (±2.7) CT acquisitions and 10.9 (±5.7) MRI acquisitions. There was non-concordance between the official report and expert review for 27 (71.1%) ears on CT and 27 (56.3%) ears on MRI. CONCLUSIONS: These data demonstrate high variability in protocols and quality of medical imaging of children with sensorineural hearing loss. Interpretation of images is highly discordant between official reports and tertiary review. Given these results, we recommend that these children be imaged and evaluated at centers with neuroradiologists who are experienced in interpreting congenital abnormalities of the cochleovestibular system.

New SMS classification of cochleovestibular malformation and its impact on decision-making.

OBJECTIVE: To propose a new classification of inner-ear anomalies that is more clinically oriented and surgically relevant: the SMS (Sawai Man Singh) classification of cochleovestibular malformations. METHODS: A retrospective multicentric study was conducted of 436 cochlear implantations carried out in 3 Indian tertiary care institutes. Patients with anomalous anatomy were included and classified, as per the new SMS classification, into cochleovestibular malformation types I, II, III and IV, based on cochlear morphology, modiolus and lamina cribrosa. RESULTS: There were 19, 23, 8 and 4 patients with cochleovestibular malformation types I, II, III and IV, respectively. Two-year post-operative Meaningful Auditory Integration Scale scores were statistically analysed. CONCLUSION: This new classification for inner-ear anomalies is a simpler, more practical, outcome-oriented classification that can be used to better plan the surgery. These merits make it a more uniform classification for recording results.

Variations in the Size and Shape of Human Cochlear Malformation Types.

The objective of this study is to determine the variations in size and shape of the most widely recognized cochlear malformation types using three-dimensional (3D) visualization. Using 3D slicer freeware, the complete inner-ear structures were segmented from 46 anonymized high-resolution computed tomography (HRCT) image datasets. Cochlear height, internal auditory canal height, and width were measured from the axial plane. Cochlear basal turn diameter was measured from the oblique coronal plane. Number of cochlear turns was measured from the 3D images and the corresponding cochlear duct length (CDL) was estimated using the CDL equations given in Alexiades et al. [Otol Neurotol 36 (2015) 904-907]. Out of 46 preoperative HRCT image datasets of human temporal bone, cochlear anatomy types including normal anatomy (4), enlarged vestibular aqueduct syndrome (3), cochlear aplasia (2), incomplete partition Types I (8), II (Mondini's deformity) (3), and III (X-linked) (4), cochlear hypoplasia (CH) (17), and common cavity (CC) (5) were identified. Majority of CH cases had cochlear height shorter than 4 mm whereas the CC cases measured cochlear height above 6 mm. For all the other malformation types, cochlear height was between 4 and 6 mm. In terms of "A" value, majority of CH cases showed shorter "A" value of <7.5 mm, which is in the lower end in comparison to the rest of the malformation types reported in this study. 3D-visualization shows the size and shape variations of all the structures of inner ear and also improves the clinicians' ability to visualize cochlear anatomy and nearby structures much easier than from the 2D image slices. Anat Rec, 302:1792-1799, 2019. © 2019 The Author. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association for Anatomy.

The common cavity vs incomplete partition type I conundrum: Decision making and management with the cochlear implant form electrode.

It has been seen that 20% of children with deafness have inner ear malformations. Studies demonstrate that Cerebrospinal Fluid (CSF) leakage occurs in 40-50% of patients with inner ear malformations. Differentiating between the various malformations pre-operatively allows the cochlear implant surgeon to plan and prepare for various difficulties associated with the management of such cases. In case of a CSF gusher, a choice of an electrode with a stopper helps in effectively closing off the cochleostomy, thus reducing the chances of post-operative infections. Case description: SM, a 10-year-old girl with the diagnosis of bilateral progressive profound hearing loss showed cochlear malformations on high resolution computed tomography (HRCT) scans of the temporal bones. A detailed study and discussion with the neuro-radiologist helped in identifying the cochleo-vestibular malformations (CVM) on both sides, thus making the choice of the better ear for electrode insertion and the type of electrode. She was subjected to left ear cochlear implantation using a lateral canal labyrinthotomy approach and a Form electrode (Med El®) with a special conical stopper was used to effectively seal the labyrinthostomy. Conclusion: Common cavity (CC) and Incomplete Partition (IP) Type I present as diagnostic challenges. Getting to the right diagnosis is of paramount importance as it helps in deciding the correct ear, choosing the correct electrode, and preparing for the surgical situations the surgeon might encounter. The Form electrode shows promise due to its unique conical seal which helps in preventing CSF leakage, thus reducing the chances of post-operative infections in cases of deformed cochlea.

Hipoacusia neurosensorial adquirida asociada a alteraciones vestibulares y / o control postural / Neurosensorial acquired hypoacusia associated with vestibular alterations and / or postural control

La otitis media aguda es una infección del oído medio con alta prevalencia en población pediátrica, las complicaciones pueden generar desde hipoacusia neurosensorial de diverso grado hasta alteración vestibular y/o control postural, aunque de ello no existen mayores reportes ni investigaciones en Chile. Por lo anterior, el objetivo fue asociar la hipoacusia neurosensorial a alteraciones vestibulares y/o de control postural. Se evaluó a un sujeto de sexo femenino, 13 años de edad, quien presentó múltiples cuadros de Otitis Media Aguda y fue diagnosticada con hipoacusia neurosensorial bilateral grado moderado. Antes del estudio, reportó desequilibrio y aumento de riesgo de caída. Se aplicaron test auditivos (timpanometría y audiometría), vestibulares (evaluación del VIII par craneal) y de control postural (posturógrafo y tests "Time up and go", Romberg y Romberg en tándem). Se encontraron alteradas la prueba de integración sensorial, con predominancia del hemicuerpo derecho, igualmente predominancia a alteraciones auditivas en el oído derecho ante pruebas que valoraron oído medio. Se observó una relación directa entre las alteraciones posturales y de equilibrio con el tipo y grado de pérdida auditiva que presenta el sujeto de estudio.

The acute otitis media is a middle ear infection with high prevalence in pediatric population, the complications could generate from sensorineural hearing loss to vestibular alteration and/or postural control, although, there aren´t report or researches of it in Chile. Therefore, the objective was to associate sensorineural hearing loss with vestibular alterations and/or postural control. We evaluated a female subject presenting multiple events of acute otitis media and she was diagnosed with sensorineural hearing loss middle grade. Before this study, she reported imbalance and falling risk. Hearing (tympanometry and audiometry), vestibular (evaluation of the VIII cranial nerve) and postural control tests were applied (posturography and "Time up and go", Romberg and Romberg in tandem test). It was found altered the integration sensorial test, with predominance to half body right and predominance of hearing impairment in the right ear to the middle ear evaluated evidence. It was observed a direct relation between postural alterations and balance with the hearing loss type from the subject of study.

Children with unilateral cochlear nerve canal stenosis have bilateral cochleovestibular anomalies.

OBJECTIVES/HYPOTHESIS: To investigate the cochleovestibular apparatus bilaterally in children with isolated unilateral bony cochlear nerve canal (bCNC) stenosis. STUDY DESIGN: Retrospective review. METHODS: Imaging studies of children with unilateral bCNC stenosis (<1.0 mm) on computed tomography imaging (N = 36) were compared with controls imaged due to trauma without temporal bone injury (N = 32). Twenty-six measurements were obtained in each ear, assessing the bony internal auditory canal (IAC), cochlea, and vestibular end-organs, and were analyzed using one-way analysis of variance for intersubject comparisons and paired t tests for intrasubject comparisons with a Bonferroni adjustment for multiple comparisons (P = .0006). RESULTS: Patients with bCNC stenosis had a smaller IAC (P < .000) and cochlea (P < .000) on the stenotic side as compared with controls. Although the vestibular end-organ was also smaller in bCNC ears, this difference was not significant. The contralateral ear also had a smaller bCNC (P < .000) and cochlea (P < .000) as compared with controls, although to a lesser degree than the stenotic side. CONCLUSIONS: Children with unilateral bCNC stenosis have abnormal biometry of both the cochlea and the vestibular end-organ in the affected and the normal contralateral ear as compared with controls. LEVEL OF EVIDENCE: 3b Laryngoscope, 129:2403-2408, 2019.

Duplicated internal auditory canal with inner ear malformation: Case report and literature review.

Internal auditory canal anomalies are rare. Narrow internal auditory canal is believed to occur as a result of aplasia or hypoplasia of the vestibulocochlear nerve. Narrow duplication of the internal auditory canal is considered to be very rare. Narrow duplication of the internal auditory canal with inner ear malformation has been reported in only 3 cases. We present 2 cases of narrow duplication of the internal auditory canal with inner ear malformation. The first case had inner ear malformation on only one side and the second case had inner ear malformation on both sides. The embryogenesis may be different between internal auditory canal and inner ear.

Position of the Internal Aperture of Vestibular Aqueduct in Patients With Enlarged Vestibular Aqueduct.

OBJECTIVE: To investigate the position of the internal aperture of vestibular aqueduct and its relationship to hearing level in patients with enlarged vestibular aqueduct (EVA). METHODS: The size of the common crus and the position of the internal aperture of vestibular aqueduct were compared among control subjects, EVA patients with and without other inner ear malformations. Auditory steady-state response thresholds were compared between EVA patients with different positions of internal apertures. RESULTS: The common crus in EVA patients was shorter than in control subjects (p < 0.05). The internal aperture of the vestibular aqueduct opened solely into the common crus in control subjects, simultaneously into the common crus and vestibule in almost 45% of EVA patients, solely into the common crus, and the vestibule in almost 30 and 25% of EVA patients, respectively. Auditory steady-state response thresholds at 2000 and 4000 Hz were higher in EVA patients whose internal apertures of vestibular aqueducts opened simultaneously into the common crus and vestibule than in those whose internal apertures opened solely into the common crus. CONCLUSION: The common crus is shorter in EVA patients than in control subjects. The internal aperture of the vestibular aqueduct opens solely into the common crus in control subjects. It opens simultaneously into the common crus and vestibule in almost half of the EVA patients. The EVA patients whose internal apertures of vestibular aqueducts open solely into the common crus may have better hearing than those whose internal apertures open simultaneously into the common crus and vestibule.

[Optimization of the approach to the spiral (Rosenthal's) canal of the cochlea in the patients presenting with cochlear-vestibular abnormalities].

The objective of the present study was to improve the effectiveness of cochlear implantation (CI) in the patients presenting with cochlear-vestibular abnormalities based on the development and practical application of the algorithm for the insertion of an electrode arrayinto the spiral (Rosenthal's) canal of the cochlea taking into consideration the specific anatomical features of the middle and inner ears. The study included 25 patients with congenital malformations of the inner ear and bilateral grade IV sensorineural loss of hearing or deafness selected for CI. Indications for drilling a cochleostomy were the high localizationof the jugular bulb and the absence of its bone wall (5 patients, 20%). In the remaining cases, it proved possible to identify the round window and perform the transmembrane insertion of the active electrode. In 15 (69%) patients, the surgical intervention provoked intraoperative leakage of the cerebrospinal fluid that was successfully stopped by the careful tamponade of either the cochleostoma or the round window niche with the use of an automuscular flap. Taken together, good visualization of the round window and the transmembrane insertion of the active electrode into the spiral (Rosenthal's) canal of the cochlea in the patients presenting with cochlear-vestibular abnormalities made it possible to reduce to a minimum the injury to the spiral organ of the cochlea, control liquorrhea, and improve auditory performance in the postoperative period.

Histopathology of inner ear malformations: Do we have enough evidence to explain pathophysiology?

OBJECTIVE: To investigate the histopathology of inner ear malformations (IEMs) in order to explain their pathophysiology. METHOD: Light microscopy was used to study 33 specimens exhibiting various IEMs in the collection of the Otopathology Laboratory at Harvard University's Massachusetts Eye and Ear Infirmary. RESULTS: The investigation found 18 incidences of cochlear hypoplasia (CH) (3 CH-I, 10 CH-II, 5 CH-III), 11 incomplete partitions (IPs) (5 IP-I, 6 IP-II), 2 vestibular dilatations, and 2 cases of cochlear nerve aplasia. The IP-I cases had characteristic defective endosteums, while the IP-II cases showed hydropic changes in the scala vestibuli. The CH cases were small in size externally, with normal or defective internal architecture. CONCLUSION: In combination with embryological data, these findings suggest that cases of CH-III and CH-IV are most probably genetically predetermined to be small in size, and that development of the membranous labyrinth stops at a point earlier than normal, so that it is shorter. At the time of complete ossification, this results in a cochlea with small external dimensions and normal internal architecture. In CH-I and CH-II cases, there is arrested development of the internal architecture, in addition to a small cochlea; it is most likely that in these cases, there is a severely defective vascular supply from the internal auditory canal (IAC). IP-I may be the result of a defective vascular supply from the blood vessels of the IAC. In IP-II, an enlarged endolymphatic sac (EES) appears to be the genetic abnormality that causes the other abnormalities, as it allows high pressure to be transmitted into the cochlea and vestibule. In IP-III, the pathophysiology appears to be an abnormal vascular supply from the middle ear mucosa, caused by a genetic abnormality and resulting in a thinner otic capsule and the absence of the modiolus.

Clinical observations and molecular variables of patients with hearing loss and incomplete partition type III.

OBJECTIVES/HYPOTHESIS: To analyze the clinical manifestations and genetic features of patients with hearing loss (HL) and incomplete partition (IP) type III malformation, and to evaluate speech performance after cochlear implantation (CI) in these patients. STUDY DESIGN: Individual retrospective cohort study. METHODS: Of 206 probands with inner ear malformations (IEMs), we constructed a homogeneous cohort of 11 genetically documented IP type III (DFNX2). Mutations affecting POU3F4 were classified as extension (n = 2), truncation (n = 3), large genomic deletion (n = 2), or missense substitution (n = 4). Postoperative outcomes were rigorously assessed with focus on POU3F4 genotypes and compared with 80 age-matched implantees without IEMs. RESULTS: HL in our cohort was prelingual in onset irrespective of degree. Serviceable hearing was obtained by wearing conventional hearing aids in three, and eight subjects required CI. No correlation was found between mutation types and initial auditory phenotype. As for the eight cochlear implantees, average Categories of Auditory Perception score was <1 preoperatively and 3.9 at 2 years post-CI. Speech performances improved over the first 3 months postoperatively in a manner comparable to implantees without IEMs. However, it then tended to slow down until 1 year postoperatively, leading to worse scores at 2 years than implantees without IEMs. Furthermore, this was more evident in those with a truncation or deletion mutation. CONCLUSIONS: CI surgeons should be aware that postoperative auditory performance may be not as good in IP type III patients as in patients without IEMs. In particular, our study implies that certain types of POU3F4 mutations may have poorer prognoses than other types after CI. LEVEL OF EVIDENCE: 4. Laryngoscope, 126:E123-E128, 2016.

A new classification of cochleovestibular malformations and implications for predicting speech perception ability after cochlear implantation.

OBJECTIVES: The aims of this study were to introduce a new classification of cochleovestibular malformation (CVM) and to investigate how well this classification can predict speech perception ability after cochlear implantation in children with CVM. METHODS: Fifty-nine children with CVM who had used a cochlear implant for more than 3 years were included. CVM was classified into 4 subtypes based on the morphology of the cochlea and the modiolus on temporal bone computed tomography (TBCT): normal cochlea and normal modiolus (type A, n = 16), malformed cochlea and partial modiolus (type B, n = 31), malformed cochlea and no modiolus (type C, n = 6), and no cochlea and no modiolus (type D, n = 6). Speech perception test scores were compared between the subtypes of CVM using analysis of covariance with post hoc Bonferroni test. Univariate and multivariate regression analyses were used to identify the significant predictors of the speech perception test scores. RESULTS: The speech perception test scores after implantation were significantly better in children with CVM type A or type B than in children with CVM type C or type D. The test scores did not differ significantly between the implanted children with CVM type A or type B and those without CVM. In univariate regression analysis, the type of CVM was a significant predictor of the speech perception test scores in implanted children with CVM. Multivariate regression analysis revealed that the age at cochlear implantation, cochlear nerve size and preimplantation speech perception test scores were significant predictors of the postimplantation speech perception test scores. The chance of cochlear nerve deficiency increased progressively from CVM type A to type D. CONCLUSION: The new classification of CVM based on the morphology of the cochlea and the modiolus is simple and easy to use, and correlated well with postimplantation speech perception ability and cochlear nerve status. This simple classification of CVM using TBCT with cochlear nerve assessment by magnetic resonance imaging is helpful in the preoperative evaluation of children with CVM.

[A rare cause of recurrent meningitis in children: cochleovestibular dysplasia]. / Une cause rare de méningite récurrente chez l'enfant: la dysplasie cochléovestibulaire.

Recurrent bacterial meningitis is an uncommon disease of childhood. It occurs most often in children who have an underlying predisposing disorder that can result from anatomic fistula or immunodeficiency. Cochleovestibular dysplasia is a rare malformation of the inner ear that is often associated with translabyrinthine cerebrospinal fistula and then can cause recurrent bacterial meningitis. We report an unusual case of recurrent meningitis revealing cochleovestibular dysplasia in a 9-year-old child. The malformation was confirmed by imaging and the child had surgery. The outcome was favourable with no recurrence of meningitis during the 3 years after the operation.