Face and content validation of a novel three-dimensional printed temporal bone for surgical skills development.

OBJECTIVE: To assess the face and content validity of a novel synthetic, three-dimensional printed temporal bone for surgical skills development and training. METHODS: A synthetic temporal bone was printed using composite materials and three-dimensional printing technology. Surgical trainees were asked to complete three structured temporal bone dissection exercises. Attitudes and impressions were then assessed using a semi-structured questionnaire. Previous cadaver and real operating experiences were used as a reference. RESULTS: Trainees' experiences of the synthetic temporal bone were analysed in terms of four domains: anatomical realism, usefulness as a training tool, task-based usefulness and overall reactions. Responses across all domains indicated a high degree of acceptance, suggesting that the three-dimensional printed temporal bone was a useful tool in skills development. CONCLUSION: A sophisticated three-dimensional printed temporal bone that demonstrates face and content validity was developed. The efficiency in cost savings coupled with low associated biohazards make it likely that the printed temporal bone will be incorporated into traditional temporal bone skills development programmes in the near future.

Clinical presentation of a group of NF2 patients to a tertiary referral skull base unit.

The objective of the investigation was to document the clinical presentations of a group of patients with neurofibromatosis type two syndrome (NF2), and took the form of a retrospective case note review. The investigation took place in the tertiary referral skull base unit. The dominant presentation of patients with NF2 is with auditory/vestibular symptoms (56%), with a smaller proportion of presentations being due to non-acoustic intracranial and spinal tumours (44%). At the time of presentation the majority of clinically significant tumours could be demonstrated in each patient with MRI of the head and spine, with few new tumours arising during the subsequent follow-up period. The range of presentation of patients with NF2 results in their management being fragmented into a variety of clinical setting, diluting the experience amassed in any one centre.

Recurrence of symptoms following treatment of posterior semicircular canal benign positional paroxysmal vertigo with a particle repositioning manoeuvre.

A consecutive series of 51 patients (34 females and 17 males) with posterior semicircular canal benign positional paroxysmal vertigo (BPPV) were treated with the modified Epley particle positioning manoeuvre (PRM). Follow-up data were available on all 51 patients. After one manoeuvre, 42 patients had a negative Dix-Hallpike test, and after a second manoeuvre, 8 of the remaining 9 patients had a negative Dix-Hallpike test (testing was conducted 1 to 2 weeks after the PRM was performed). Therefore, the overall short-term success rate after two manoeuvres was 50 of 51 patients (98%), which is similar to other series. A follow-up questionnaire to determine the incidence of recurrence of symptoms was administered after a minimum period of 30 weeks. Twenty-three patients reported a recurrence (or, in the case of the one treatment failure, persistence) of their symptoms (45%). Therefore, although virtually all patients can be treated successfully with the PRM, almost half of these patients can be expected to experience a further recurrence of symptoms. This long-term recurrence rate is higher than has previously been reported and is a significant factor clinicians must be aware of in their treatment of this condition. In particular, this finding emphasizes the need for patient counselling with regard to the likelihood of recurrence and access to follow-up treatment if recurrence occurs.

Postoperative quality of life in vestibular schwannoma patients measured by the SF36 Health Questionnaire.

OBJECTIVE: To quantify the postoperative quality of life in patients following surgical treatment for vestibular schwannoma. STUDY DESIGN: Patient self-assessment using the short form 36 (SF36) multidimensional quality of life health questionnaire. Sex- and age-matched normalized scores were calculated using a standardized process and accepted normative data. SETTING: Tertiary referral skull base unit. RESULTS: An 80% response rate (90 patients) was achieved. The postoperative quality of life in vestibular schwannoma patients, as quantified by seven of the eight SF36 health scales was less than the appropriate matched healthy standard. Comparison of a variety of preoperative patients and tumor factors-different operative approaches (translabyrinthine and retrosigmoid), tumor size (group cut of points of tumor diameter 1.5 mm and 2.5 mm), patient sex, and ranking of patient age-showed no statistically significant difference in measured quality of life outcomes for each of these traditional predictors. CONCLUSION: Reduced quality of life in patients after surgical treatment for vestibular schwannoma, coupled with the low tumor growth rates and minimal preoperative symptoms, supports a conservative approach to patient management. The advantages and disadvantages of a variety of approaches used to measure the quality of life after surgical treatment of vestibular schwannoma and their impact on clinical decision making for patients, are discussed.

Hearing preservation in solitary vestibular schwannoma surgery using the retrosigmoid approach.

The results of 50 cases of vestibular schwannoma surgery with hearing preservation performed by the retrosigmoid approach at Addenbrooke's Hospital, Cambridge, during a 10-year period are presented. The hearing-preservation rate, using audiometric criteria set by others as "serviceable hearing" (Wade PJ, House W. Otolaryngol Head Neck Surg 1984;92:1184-93; Silverstein H, et al. Otolaryngol Head Neck Surg 1986;95:285-91; Cohen NL, et al. Am J Otol 1993;14:423-33) was 8% (4 of 50 cases). When the more stringent selection criteria of near-normal hearing and reporting criteria of socially useful hearing preservation (pure-tone average < 30 dB/speech discrimination score > 70%) is used, the hearing-preservation rate is 4.8% (1 of 21 cases). The only preoperative factor that may predict a favorable hearing-preservation outcome is normal auditory brain stem response morphology (Fisher's exact 2-tailed test, P < 0.001). The number of suitable candidates for hearing-preservation surgery are few. Reasonable indications for attempted vestibular schwannoma surgery with hearing preservation are discussed.

Does choice of hearing selection criterion and reporting criteria affect the hearing preservation rate in vestibular schwannoma surgery?

With increasing refinement in the surgery of vestibular schwannoma the aims of complete tumor removal and facial nerve preservation have been largely fulfilled. However, the reputation of and place for hearing-preservation surgery still remain uncertain. A major part of this uncertainty is the result of difficulties in interpretation of the various reported results of hearing-preservation surgery. Meaningful comparison between series is difficult because of the varied number of postoperative reporting criteria commonly in use today. Although it is acknowledged that the postoperative reporting criteria affect the hearing-preservation rates, what is not readily appreciated is that preoperative selection criteria for hearing-preservation cases can also significantly affect the success rate of hearing-preservation acoustic neuroma surgery. This article models the many possible outcomes of hearing-preservation schwannoma surgery by use of the previously reported Cambridge series as an illustrative example. With these models some understanding can be gained of the effect of choosing various preoperative and postoperative hearing criteria on the overall hearing-preservation success rate.

Use of autologous osteocyte containing bone pate for closure of tegmental defects.

OBJECTIVE: This article aimed to describe a new technique for the reconstruction of middle fossa tegmental defects using autologous osteocyte containing bone pate. STUDY DESIGN: The technique is demonstrated using clinical photographs and x-ray examples of tegmental defects. TECHNIQUE: Pliable bone pate graft is manufactured using autologous bone dust, blood, iodine solution, and tissue glue (Tisseel; Immuno, Austria). The graft is placed accurately via a combined mini-middle fossa craniotomy and middle mastoidectomy approach. CONCLUSION: This new technique of middle fossa bony tegmental repair has considerable advantages over previously described methods that use rigid or synthetic materials.

An alternative method for dealing with cerebrospinal fluid fistulae in inner ear deformities.

OBJECTIVE: This study aimed to review the management of cerebrospinal fluid (CSF) fistulae in the setting of developmental inner ear deformity. STUDY DESIGN: The study design was a case review, close examination of preoperative radiology, and corresponding intraoperative images. TECHNIQUE: A definitive method of CSF fistula closure is described using previously known techniques used commonly in skull base surgery. CONCLUSIONS: The use of a multiple-level, reinforced wound closure technique is necessary to definitively close CSF fistulae in extreme inner ear deformity and to prevent further episodes of CSF leak and meningitis.

Drill-induced hearing loss in the nonoperated ear.

The reversible hearing loss in the nonoperated ear noted by patients after ear surgery remains unexplained. This study proposes that this hearing loss is caused by drill noise conducted to the nonoperated ear by vibrations of the intact skull. This noise exposure results in dysfunction of the outer hair cells, which may produce a temporary hearing loss. Estimations of outer hair cell function in the nonoperated ear were made by recording the change in amplitude of the distortion-product otoacoustic emissions before and during ear surgery. Reversible drill-related outer hair cell dysfunction was seen in 2 of 12 cases. The changes in outer hair cell function and their clinical implications are discussed.

Pacemaker region in a rhythmically contracting embryonic epithelium, the enveloping layer of Oryzias latipes, a teleost.

The primary objectives of this study were to determine the embryonic stage at which the Oryzias latipes enveloping layer (EVL) begins to contract rhythmically, and to determine where these contractions arise within the EVL. Using time-lapse video recording, we showed that the contractions begin at stage 14 (the stage of the embryonic shield) and arise in the ventral region of the EVL, which is centered at 180 degrees longitude from the embryonic shield. We have called this the pacemaker region for the contractions. Using fluorescein diacetate as a vital stain, we showed that the ventral region of the EVL continues to act as a pacemaker even after the EVL is detached from the rest of the egg. Rhythmic contractile activity ceased when we removed a group of about 130 cells--10% of the total EVL--from the pacemaker region; comparably large wounds elsewhere had no effect on the contractions. When we cut detached EVLs into ten pieces, only 2.4 +/- 1.8 (mean +/- SD, N = 11) of them contracted rhythmically, even though a considerably larger proportion of the EVL cells participate in the contractions in undisturbed blastoderms. We conclude that the pacemaker cells are necessary for rhythmic contractile activity and that cells outside this region do not contract spontaneously. The contractile waves are propagated at a velocity of 14-54 microns sec-1. This value, which is two to three orders of magnitude slower than the propagation of epithelial action potentials, is similar to the rate of propagation of waves of increased cytosolic Ca2+ in other systems. We propose that the medaka EVL is a good system in which to study certain aspects of epithelial morphogenesis.