Preservation of hearing in acoustic tumor surgery: audiologic indicators

Auditory Brain Stem Response Predictors of Hearing Outcomes after Middle Fossa Resection of Vestibular Schwannomas

Objectives To analyze the relationship between preoperative and intraoperative auditory brain stem response (ABR) characteristics and hearing outcomes in patients with vestibular schwannomas (VS) undergoing hearing preservation (HP) surgery via a middle cranial fossa (MCF) approach.

Design Prospective study.

Setting Academic tertiary skull base referral center.

Methods Pre- and postoperative pure-tone average (PTA) and word recognition score (WRS) were examined. Intraoperative ABR wave III latency, wave V latency, and amplitude were recorded. HP was defined as postoperative WRS ≥50%.

Participants Adult patients with VS and WRS ≥50% who underwent MCF tumor resection between November 2017 and September 2019.

Main Outcome Measures Postoperative hearing outcomes.

Results Sixty patients were included. Mean tumor size was 9.2 mm (range, 3–17). HP rates were 56.7% for the cohort and 69.7% for tumors <10 mm. A complete loss of wave V was associated with an 82.9% increase in postoperative PTA (p < 0.001) and 97.2% decrease in WRS (p < 0.001), whereas a diminished wave V was correlated with 62.7% increase in PTA (p < 0.001) and 55.7% decrease in WRS (p = 0.006). A diminished or absent wave V, but not increased wave III/V latency or decreased wave V amplitude, was correlated with a decline in postoperative hearing class (r = 0.735, p < 0.001). Receiver-operating characteristic analysis demonstrated that a stable wave V has the highest accuracy in predicting HP (sensitivity of 82.6%, specificity of 84.8%).

Conclusion Of the examined preoperative and intraoperative ABR characteristics, a stable wave V intraoperatively was the strongest predictor of HP after MCF resection of VS.

Level of Evidence Level III.

Cost-Effective Evaluation of Asymmetric Sensorineural Hearing Loss with Focused Magnetic Resonance Imaging

The poor sensitivity of audiometric brain stem response for small vestibular schwannomas (acoustic neuromas) creates a dilemma for the physician evaluating a patient with signs and symptoms of retrocochlear disease. Magnetic resonance imaging is recognized as the gold standard for the evaluation of these problems, but if a complete examination of the internal auditory canals and head is done on every patient, the cost is high. Although less expensive, screening with audiometric brain stem response risks missing up to 33% of small tumors. Therefore we developed a focused magnetic resonance imaging sequence for evaluation of patients with asymmetric sensorineural hearing loss and/or nonpulsatile tinnitus. The protocol includes a T1-weighted sagittal localizer, pregadolinium and post-gadolinium T1-weighted 3-mm contiguous axial slices through the internal auditory canal and the region of the cerebellopontine angle, and T2-weighted axial images through the entire brain. Total scanning time is about 12 minutes, and the estimated cost is $300 to $500. We retrospectively reviewed the imaging records of 485 screening examinations done during an 18-month period. Twenty-four patients had diagnoses definitely or probably producing the hearing loss for an overall positive rate of 5%. By eliminating the need for follow-up audiometric or electrophysiologic studies, we believe a focused magnetic resonance imaging-based diagnostic scheme is actually more cost-effective on a cost-per-patient basis.

Patterns of hearing loss following retrosigmoid excision of unilateral vestibular schwannoma

Objectives To determine the pattern of auditory responses, time-course of hearing deterioration, and possible site of lesion following retrosigmoid excision of unilateral vestibular schwannomas. Design Prospective, nonrandomized, observational pilot study. Setting Tertiary referral medical center. Main outcome measures Preoperative and postoperative pure-tone and speech audiometry, auditory brainstem response testing, and distortion product otoacoustic emissions were performed in 20 patients. Testing was conducted every 24 hours for the duration of hospitalization. Transtympanic electrocochleography was performed if delayed deterioration of auditory responses was documented. Results Of the 20 patients, 7 had no discernible cochlear nerve at the end of the procedure. Of the 13 patients with an intact nerve, 6 retained hearing, 3 with evidence of reduced neural function. Of the 7 who lost hearing despite an intact nerve, 5 lost at least cochlear and possibly also neural function, and 1 had reduced neural function but retained cochlear function. There were two examples of delayed deterioration of cochlear nerve responses. Conclusions Hearing loss following retrosigmoid removal of vestibular schwannomas most often involves loss of at least cochlear function, possibly in addition to neural damage. In a smaller number of cases anacusis or hearing deterioration can be attributed to purely neural trauma.

Hearing preservation: microsurgery

PURPOSE OF REVIEW

To evaluate the recent and significant contributions to the literature that examine hearing preservation outcomes and prognostic factors in vestibular schwannoma microsurgery.

RECENT FINDINGS

Hearing preservation rates overall range considerably between 2 and 93% in recent studies. There are a number of factors that have been reported to be significant in the prediction of hearing preservation. Characteristics such as approach, results of preoperative neurophysiological testing, tumor size and nerve of origin have long been reported. A more recent contribution to the literature has included the association between MRI T2 signal in the fundus of the internal auditory canal and hearing preservation. This review provides a summary of some of the landmark studies in conjunction with more recent work detailing the prognostic factors for hearing preservation in the surgical management of vestibular schwannoma.

SUMMARY

Hearing preservation in vestibular schwannoma surgery has undergone tremendous evolution over the past 50 years. In this review, we outline the prognostic factors that predict hearing preservation and describe recent contributions.

Factors influencing hearing preservation in acoustic tumor surgery

In patients who underwent neurosurgery for excision of acoustic tumors, we used correlation and multivariate logistic regression analysis to study relationships among nine variables thought to have value in predicting hearing preservation. These variables included auditory perceptual, auditory neurophysiologic, and imaging-related characteristics of acoustic tumor dimensions. The univariate correlations showed two general trends. The first trend demonstrated relationships among imaging-related acoustic tumor dimensions (size or porus acousticus widening) with either postoperative hearing or brainstem auditory evoked potential (BAEP) abnormalities (tumor size and postoperative hearing; porus acousticus widening and postoperative hearing; tumor size and preoperative BAEP abnormalities). The second trend reflected interrelationships among preoperative audiometric variables that were not related to postoperative hearing outcome. Logistic regression analysis of eight independent variables on the presence or absence of postoperative hearing found that porus acousticus widening was the best prognostic indicator for hearing outcome. When the porus acousticus was widened, the odds ratio was 11:1 that hearing would be lost postoperatively. Viewed as a whole, the literature on prognostic variables related to hearing preservation has been limited, almost entirely, to univariate relationships. To determine more accurately which preoperative variables have unique prognostic value, more complex multivariate, analysis procedures will be required. Additionally, standardized criteria for assessment and reporting of auditory test results are also needed.

Hearing preservation by the extended and nonextended middle cranial fossa approach for acoustic neuroma

The results of 248 cases of acoustic neuroma surgery carried out mainly by the extended middle cranial fossa approach during a 16-year period from 1976 to 1991 are analyzed. Hearing preservation was attempted in 69 cases and successfully achieved in 35 (51%) cases. Hearing was preserved in 24 (57%) of 42 cases in which a tumor was 20 mm or smaller in diameter, pure-tone hearing level was 50 dB or lower, and speech discrimination score was 50% or higher. The hearing preservation rate (76%) in the cases with a tumor extending 3 mm or less from the internal auditory canal was much higher than in cases with a larger tumor. Hearing was preserved in three of seven cases with a tumor of 21 mm or larger and in two of four cases of neurofibromatosis type 2. The evaluation of postoperative hearing is also discussed.

Small acoustic neuromas: surgical outcomes versus observation or radiation

OBJECTIVE

Evaluate factors affecting outcomes of small acoustic neuroma (AN) removal via a middle cranial fossa (MCF) approach, and compare results to published data on observation and radiation therapy.

STUDY DESIGN

Retrospective chart review.

SETTING

Academic tertiary referral center.

METHODS

162 consecutive patients (ages 19-70) with unilateral AN (0.2-2.5 cm in largest dimension) removed through a MCF approach were reviewed focusing on preservation of hearing, facial nerve function and complications. One hundred thirteen patients had pre-operative word recognition scores (WRS)>70%.

RESULTS

Both tumor size and pre-operative WRS were related to post-operative WRS (p<0.01). Overall, at least some hearing was preserved in 94 (60%) of the 156 patients who had hearing before surgery. If the WRS was also >70% (N=113), 56 (50%) maintained WRS>70%. Importantly, WRS for 12 others improved to >70% after surgery. When the patients were stratified by tumor size, the patients with small tumors (2-10 mm) faired better than the overall group. At least some hearing was preserved in 65 (72%) of the 90 patients. If the WRS was also >70% (N=66), 39 (59%) maintained WRS>70%. WRS for eight others improved to >70% after surgery. When the tumor was 1.1-1.4 cm (N=34), the chance of preserving some hearing decreased to 42% (14/33). If the WRS was also >70% (N=23), 9 (39%) maintained WRS>70%. WRS for three others improved to >70% after surgery. When the tumor reached 1.5-2.5 cm (N=35), the hearing preservation rate was 43%. If the WRS was also >70% (N=24), only eight (33%) maintained WRS of 70%, and one other improved to >70%. The addition of intra-operative whole eighth nerve near field monitoring improved results during small tumor (<or=1.0 cm) removal preserving some hearing in 80% (32/40) and preserving >70% WRS in 76% (22/29) of those with >70% pre-operative WRS. Good facial nerve function (HB I-II) was achieved in 97% (86% HB I). When tumor size was <or=1.0 cm (N=93), however, good facial nerve function was obtained in 100% (94% HB I). Complications included CSF leak: 9 (5.5%); seizure: 2 (1.2%); and recurrence: 1 (0.6%).

CONCLUSION

Our results suggest that removal of unilateral AN through an MCF approach when the tumor is small and hearing is good provides the best opportunity for hearing preservation and normal facial nerve function. Observation historically results in tumor growth in young and middle-age patients with subsequent hearing loss. Radiation may prevent most tumors from growing, and more data are needed to determine long-term tumor control and hearing preservation rates.

Transient Evoked Otoacoustic Emissions Pattern as a Prognostic Indicator for Hearing Preservation in Acoustic Neuroma Surgery

OBJECTIVE

To determine whether pre-operative transient otoacoustic emission (TEOAE) patterns are predictive of successful hearing preservation in acoustic neuroma surgery.

STUDY DESIGN

Retrospective observational study.

SETTING

Tertiary referral medical center.

PATIENTS

A convenience sample was identified in whom pre-operative TEOAE data were available in patients undergoing acoustic neuroma surgery from 1993-2004. Ninety-three patients were identified who met this inclusion criterion.

INTERVENTIONS

Subjects underwent attempted hearing preservation surgery via middle cranial fossa or retrosigmoid approaches. Routine audiometry, ABR, and TEOAE.

MAIN OUTCOME MEASURES

Pre- and post-operative pure tone and speech results were categorized into hearing classes A, B, C, and D as described in the American Academy of Otolaryngology guidelines (1995). Hearing preservation was defined by maintenance of the pre-operative hearing class or downgrade to within one hearing class post-op. Pre-operative TEOAE results were divided into five frequency bands and described as positive in each band if there was a response above the noise floor with >50% reproducibility.

RESULTS

Hearing was preserved in 51 patients (55%). Of these, 11 (22%) had positive TEOAE response in all five frequency bands measured (1, 1.5, 2, 3, 4 kHz), whereas 40 (78%) had TEOAE responses ranging from 0 to 4 frequency bands. 42 patients failed to preserve their hearing. Of these, only three (7%) had positive TEOAE in all five frequency bands, and 39 (93%) had TEOAE responses ranging from 0 to 4 frequency bands (p<0.05). Other variables of prognostic significance to hearing preservation in our series included smaller tumor size, tumor location within the IAC, better pre-operative hearing, and shorter latencies on ABR. Logistic regression was then used to compare the prognostic value of TEOAE against these variables. In our series, ABR latencies and 5 frequency band response on TEOAE showed the highest significant correlation to hearing preservation (p<0.05).

CONCLUSION

A robust pre-operative TEOAE frequency band pattern may be used as a favorable prognostic indicator for potential hearing preservation in acoustic neuroma surgery. The prognostic value may be enhanced when combined with other prognostic factors such as tumor size, tumor location, pre-operative ABR and audiometric results.

Preoperative predictive factors for hearing preservation in vestibular schwannoma surgery

OBJECTIVES

We performed a retrospective chart review to evaluate the various predictive factors for postoperative hearing preservation in the surgical management of vestibular schwannoma.

METHODS

Of 792 patients operated on for vestibular schwannoma between April 1987 and July 2002, 107 were candidates for hearing preservation surgery. These patients were divided into group 1 (hearing preserved) and group 2 (hearing not preserved), and both of these groups were evaluated for age, sex, pure tone average, sound discrimination score, tumor size, and auditory brain stem response parameters. A corrected chi2 test and a corrected t-test were used for statistical analysis. Multiple regression analysis was further done to evaluate independent predictive factors, either alone or in combination. The results were evaluated by use of the modified Sanna classification and the guidelines of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS).

RESULTS

Preoperative pure tone average and tumor size were the 2 predictive factors in our study. A Pearson correlation test showed that there was no multicollinearity between the factors. On multiple regression analysis by backward elimination of nonsignificant factors, we found that tumor size is an independent predictive factor for postoperative hearing. According to the modified Sanna classification, postoperative hearing was preserved in 11.2% of patients (equivalent to class A of AAO-HNS guidelines).

CONCLUSIONS

In our series, preoperative pure tone average and tumor size were found to be predictors of postoperative hearing levels.

Acoustic neuroma surgery: the results of long-term hearing preservation

OBJECTIVE

To report the long-term outcome hearing results following acoustic neuroma surgery. To determine whether changes, if any, in the thresholds of the operated ear are mirrored in the contralateral unoperated side. In addition, to identify predictive factors, if any, that may predispose individuals to hearing loss in the operated ear in the late post-operative period.

STUDY DESIGN

Retrospective patient chart review.

SETTING

University Tertiary Referral Centre.

PATIENTS

From 1978 to 1997, one hundred and twenty six patients with small acoustic neuromas (less than 2 cm as measured within in the cerebellopontine angle) underwent excision via the suboccipital (retrosigmoid) approach with the patient in the prone position. Hearing preservation was successful in 43 patients (34.1%). The audiometric data of thirty patients with a minimum follow-up interval of 36 months was analyzed. The mean follow-up period was 113.4 months (range 36-264, SD=57.8) and the mean age at surgery was 47.3 years (range 32 to 64, SD = 7.3).

OUTCOME MEASURES

Speech Reception Thresholds (SRT), Speech Discrimination Scores (SDS) and Pure-tone Audiometry (PTA, 0.5, 1 & 2 kHz) were noted on the operated and unoperated ears. The AAO Classification according to the Committee on Hearing and Equilibrium guidelines for the evaluation of hearing preservation in acoustic neuroma was used to assess hearing serviceability.

RESULTS

Subsequent to including corresponding changes in the unoperated ear, the means of the SRT and PTA in the operated ear between the early and late post-operative periods were statistically significantly different (p=0.0012 & 0.034 respectively). Twelve (40%) patients demonstrated significant deterioration in hearing thresholds over time. Pre-operatively, 96.7% of patients had serviceable hearing (Class A & B). This falls to 76.6% in the early post-operative period and to 56.7% in the late post-operative period.

CONCLUSION

Our study highlights the finding that over time a significant number of individuals realize a greater ongoing hearing loss in the post tumour excision ear than the contralateral ear.

Stacked tone-burst-evoked auditory brainstem response (ABR): preliminary findings

In 1997, Don and his co-workers described a new method for evaluating the auditory brainstem response (ABR)--yielding the stacked-wave-V ABR--which may permit the reliable detection of even small vestibular schwannomas (VSs). However, this method requires a masking technique that may not be readily available to the clinician. Furthermore, relatively high-level noise is required and may be annoying to the patient. An alternative method that might permit the same manipulation of the ABR was thus explored whereby tone-bursts (TBs) were used to obtain frequency-specific ABRs. The goal of the study was to determine whether TBs could be used to achieve the sort of de-convolution and subsequent enhancement of wave V reported with the original method of Don et al. First, the TB-stacked ABR (wave V) was compared to that obtained using derived narrowband masked ABRs in young normal-hearing subjects. Second, the TB method was employed in subjects with unilateral VSs and in patients with unilateral sensory hearing loss in a preliminary clinical trial. The observed results are promising for the use of the TB method as an alternative approach to ABR 'stacking' and warrant further research and development of the TB method.

Cochlear microphonics for hearing preservation in vestibular schwannoma surgery

OBJECTIVES

To determine whether cochlear function is beneficial in decision-making concerning the selection of hearing preservation surgery for vestibular schwannoma.

STUDY DESIGN

Retrospective review of 44 patients undergoing tumor resection with a middle fossa approach.

METHODS

Cochlear microphonics in electrocochleography together with tumor size, pure-tone average (PTA), speech discrimination score (SDS), auditory brainstem response (ABR), and compound action potentials were examined. As acoustic stimuli, short tone-bursts with frequencies of 0.5, 1, and 2 kHz were employed to measure cochlear microphonics and a click was used to obtain compound action potentials. We determined detection thresholds of cochlear microphonics and action potentials.

RESULTS

The overall rate of preservation of serviceable hearing was 59.1% (26/44). There were significant differences between patients with and without serviceable postoperative hearing in PTA, SDS, finding of ABR, compound action potential detection threshold, and mean cochlear microphonic detection threshold (at 0.5, 1, and 2 kHz). However, tumor size was unrelated to hearing outcome. Serviceable hearing was preserved in 23 (76.7%) of 30 patients, with a mean cochlear microphonic detection threshold of 40 dB nHL or less, suggesting normal or slightly impaired cochlear function. Hearing recovery was recognized in three patients, who also had a mean cochlear microphonic detection threshold of 40 dB nHL or less. Of the three patients, two had lower cochlear microphonic detection thresholds than audiometric thresholds, demonstrating the existence of a retrocochlear component in their hearing loss.

CONCLUSIONS

The cochlear microphonic detection threshold predicts not only hearing preservation but also hearing improvement in patients with vestibular schwannomas.

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.

Hearing preservation in patients undergoing vestibular schwannoma surgery: comparison of middle fossa and retrosigmoid approaches

OBJECT

The goal of this retrospective study was to evaluate hearing preservation after surgery for vestibular schwannoma in which the middle fossa (MF) or retrosigmoid (RS) approaches were used. Hearing preservation in vestibular schwannoma surgery can be achieved by using either the MR or RS approach. Comparative outcome data between these approaches are lacking, and, as a result, selection has generally been determined by the surgeon's preference.

METHODS

The authors have compared removal of small vestibular schwannomas via MF and RS approaches with regard to hearing preservation and facial nerve function. The study group was composed of consecutively treated patients with vestibular schwannoma, 48 of whom underwent operation via an MF approach and 50 of whom underwent the same number of RS operations. Tumors were divided into size-matched groups. Hearing results were recorded according to the American Academy of Otolaryngology-Head and Neck Surgery criteria, and facial nerve outcome was recorded as the House-Brackmann grade. Overall, 26 (52%) of the patients treated via the MF approach achieved a Class B or better hearing result compared with seven (14%) of the RS group. Some hearing was preserved in 32 (64%) of the patients in the MF group and in 17 (34%) of the RS group. The results obtained by using the MF approach were superior for intracanalicular tumors (p=0.009, t-test), and for tumors with a cerebellopontine angle (CPA) component measuring 0.1 to 1 cm (p=0.006, t-test). For tumors in the CPA that were 1.1 to 2 cm in size, our data were inconclusive because of the small sample size. Facial weakness was seen more frequently after MF surgery in the early postoperative period, but results were equal at 1 year.

CONCLUSIONS

The results of this study have demonstrated a more favorable hearing outcome for patients with intracanalicular tumors and tumors extending up to 1 cm into the CPA that were removed via the MF when compared with the RS approach.

Acoustic neuroma presented as repeated hearing loss

Up to 15% of patients with acoustic neuroma may have a history of sudden hearing loss. Recovery from sudden hearing loss with acoustic neuroma is rare. In this paper, a case of bilateral acoustic neuromas presented as repeated sudden hearing loss with recovery on the left side after removal of right-sided tumor were reported. She experienced three episodes of sudden hearing loss, showing various types of audiograms and ABR on the left side. There was no relationship between the type of audiograms and ABR findings. Factor influencing ABR might be different from the cause of hearing impairment. Acoustic neuromas can be reliably identified by performing MRI properly. However, MRI showed negative scan and ABR finding was abnormal in the first episode of our case. ABR continues to be a sensitive diagnostic back-up test to MRI for the detection of acoustic neuromas. Even if the patient, who showed abnormal ABR findings suggesting retrocochlear pathology, showed normal MRI, acoustic neurinoma should not be ruled out and both ABR and MRI must be re-examined at regular intervals.

Hearing preservation and improvement of auditory brainstem response findings after acoustic neuroma surgery

Among 9 patients with acoustic neuroma who underwent tumor removal by the middle cranial fossa approach during the past 5 years, 6 were selected for hearing preservation surgery which was successful in 5 cases (83.3%). For the prediction of success in hearing-preservation, factors related to hearing preservation, including preoperative findings of neurotological examination, were analyzed. Postoperative hearing threshold correlated significantly with wave V latency and I-V interpeak latency of preoperative auditory brainstem response (ABR) and the SP/AP ratio of preoperative electrocochleogram and postoperative facial palsy. The size of tumors and preoperative results of speech audiometry did not correlate with hearing results. Postoperative ABR findings were normalized within the observation period from 5 days to 10 months in 3 hearing-preserved patients. Possible mechanisms for improvement of ABR findings after the removal of acoustic neuroma are discussed.

Hearing preservation in acoustic neurinoma surgery

The authors have reviewed hearing results obtained in 99 patients operated on via the suboccipital approach for acoustic neurinoma, who were not deaf prior to surgery (pure tone average less than 70 dB). Tumor size was less than 10 mm in four cases, 10 to 19 mm in 26 cases, 20 to 29 mm in 39 cases, and 30 mm or greater in 30 cases. Removal was macroscopically complete in 92 cases and incomplete in seven, including four cases with bilateral acoustic neurofibromatosis. Hearing was preserved in 29 patients (29.3%), of whom 23 had neurinomas smaller than 30 mm and six had tumors exceeding 30 mm in size. Postoperative hearing was good in eight cases (four with neurinomas less than 20 mm and four with neurinomas greater than 20 mm), serviceable in four cases (three with neurinomas less than 20 mm and one with a tumor greater than 30 mm), and poor in 17 cases (eight with neurinomas less than 20 mm and nine with tumors greater than 20 mm). Fifty-seven patients underwent intraoperative brain-stem auditory evoked potential monitoring: the rate of hearing preservation was found to be higher in this group than in the 42 without monitoring (p less than 0.05). A statistical study using stepwise regression analysis showed that the two preoperative factors most significantly associated with postoperative hearing preservation are a good auditory level for low frequencies measured by pure tone audiometry and a small-sized tumor. Overall results indicate that, even if hearing is more easily preserved when the neurinoma is small and the preoperative auditory condition is good, the surgeon should try to save hearing in all patients who have preserved hearing before surgery.

Acoustic neuroma: a cost-effective approach

A cost-effective approach to the diagnosis and treatment of acoustic neuromas continues to evolve as diagnostic methods improve. In the past 7 months, since gadolinium-enhanced magnetic resonance imaging (MRI) has become available in our practice, our screening and presurgical workup has changed. The purpose of this article is to outline the current philosophy of the senior authors in relation to acoustic neuroma management on the basis of 72 patients diagnosed from July 1988 to February 1989. With more sensitive diagnostic means, older less sensitive studies may be eliminated from the routine workup, thus maintaining cost-effectiveness while preserving the highest standard of patient care. The body of this article will review our current use of the many available diagnostic options and emphasize a cost-effective approach.