2.1

Subjects

Following departmental and institutional review board approval at the University Hospitals Case Medical Center Institutional Review Board for Human Investigation (IRB # 09-10-05), the cochlear implant database at University Hospitals Case Medical Center was reviewed. Both paper and electronic chart reviews were conducted on 456 patients implanted between September 2002 and August 2010. In addition to demographic data, the CI and patient database was searched for the type of implant manufacturer, surgical procedure (unilateral, bilateral or revision), population (pediatric or adult), presence of cochlear malformations or ossification, and surgical and operative time. Thirty-two patients with incomplete medical records were excluded. Prior to 2005, electronic medical records had not been implemented at our hospital. The surgical and operative times were typically charted in the anesthesia paper record. Start times and times in and out of the operating room were either incompletely recorded or not available in 32 patients leaving a total of 424 patients to be included in the final analysis.

2.2

Surgical technique

All surgeries were performed under general anesthesia. Facial nerve monitoring was used in all cases. A mastoidectomy with facial recess approach was used. A seat was created in the parietal bone and the internal receiver stimulator was placed in a subperioteal pocket. The electrode array was introduced atraumatically through the cochleostomy into the scala. Free muscle graft was used to pack the cochleostomy. If applicable the ground electrode was placed in a pocket underneath the temporalis muscle. Depending on the surgeon’s preference, tie-down sutures were placed to fix and stabilize the device. Residents’ involvement varied depending on their training levels and surgical skills. Progressively, trainees performed the mastoidectomy and the facial recess, and when appropriate, the electrode insertion. Routinely, an audiologist conducted neural response telemetry and confirmed adequate impedances prior to extubation.

Anterior–posterior skull plain radiographs were taken prior to extubation in pediatric patients, and in the post-operative recovery area in adult patients.

2.3

Outcomes assessment

The times at which the patient entered the operating room, the incision was made, the surgery was concluded and the patient exited the operating room were recorded using both hospital electronic and paper chart records. The anesthesia paper charting was reviewed when electronic records were not available. The surgical duration (SD) was defined as the time elapsed, in minutes, between the initial surgical incision and complete wound closure, including the neural response telemetry and impedance testing. The total operative room time (TORT) was defined as the time elapsed, in minutes, between patient entry into the operating room and when he or she exited the room. For the vast majority of patients, exact SD and TORT times were extracted from the patient’s charts.

When the incision time was not clearly recorded the cautery start time was used as a substitute. For those patients for whom the total operative time times were recorded but surgical times were missing, an estimated time was calculated based on the average time difference between OR entry and surgery start time, and between surgical end time and OR. For this minority of patients, a mean additional time of 37 ± 7 min was added prior to the start of the surgery or after the time in the operating room, and 15 ± 6 min was added to the end surgical time, resulting in a mean total additional time of 52 ± 13 min.

Cochlear implantation SD and TORT were compared between both pediatric (≤ 18 years of age) and adult (> 18 years of age) implantees, as well as between unilateral, bilateral and revision CI with or without the assistance of a resident.

At our teaching institution, typically residents in their fourth post-graduate year complete a four-month rotation through the Otology/Neurotology service. In addition, comparisons were made between years of the procedure, primary as compared to revision surgery, and the relative complexity of the surgical procedure (existence or absence of cochlear ossification or malformed inner ear).

2.4

Data analysis

Data from the chart review were collected and entered into an Excel file, and imported into a statistical program (SPSS 20) for analysis. Both parametric and nonparametric statistics were used, as appropriate. Statistical analysis was done using the t-test for comparison of means, the Mann–Whitney test for comparison of median when appropriate and the one-way ANOVA and p-values for Tukey’s multiple comparison procedure. Simple linear regression was used to assess the correlation between SD, TORT and the other variables. Criterion for statistical significance was set at p ≤ 0.05, two-tailed.

2.1

Subjects

Following departmental and institutional review board approval at the University Hospitals Case Medical Center Institutional Review Board for Human Investigation (IRB # 09-10-05), the cochlear implant database at University Hospitals Case Medical Center was reviewed. Both paper and electronic chart reviews were conducted on 456 patients implanted between September 2002 and August 2010. In addition to demographic data, the CI and patient database was searched for the type of implant manufacturer, surgical procedure (unilateral, bilateral or revision), population (pediatric or adult), presence of cochlear malformations or ossification, and surgical and operative time. Thirty-two patients with incomplete medical records were excluded. Prior to 2005, electronic medical records had not been implemented at our hospital. The surgical and operative times were typically charted in the anesthesia paper record. Start times and times in and out of the operating room were either incompletely recorded or not available in 32 patients leaving a total of 424 patients to be included in the final analysis.

2.2

Surgical technique

All surgeries were performed under general anesthesia. Facial nerve monitoring was used in all cases. A mastoidectomy with facial recess approach was used. A seat was created in the parietal bone and the internal receiver stimulator was placed in a subperioteal pocket. The electrode array was introduced atraumatically through the cochleostomy into the scala. Free muscle graft was used to pack the cochleostomy. If applicable the ground electrode was placed in a pocket underneath the temporalis muscle. Depending on the surgeon’s preference, tie-down sutures were placed to fix and stabilize the device. Residents’ involvement varied depending on their training levels and surgical skills. Progressively, trainees performed the mastoidectomy and the facial recess, and when appropriate, the electrode insertion. Routinely, an audiologist conducted neural response telemetry and confirmed adequate impedances prior to extubation.

Anterior–posterior skull plain radiographs were taken prior to extubation in pediatric patients, and in the post-operative recovery area in adult patients.

2.3

Outcomes assessment

The times at which the patient entered the operating room, the incision was made, the surgery was concluded and the patient exited the operating room were recorded using both hospital electronic and paper chart records. The anesthesia paper charting was reviewed when electronic records were not available. The surgical duration (SD) was defined as the time elapsed, in minutes, between the initial surgical incision and complete wound closure, including the neural response telemetry and impedance testing. The total operative room time (TORT) was defined as the time elapsed, in minutes, between patient entry into the operating room and when he or she exited the room. For the vast majority of patients, exact SD and TORT times were extracted from the patient’s charts.

When the incision time was not clearly recorded the cautery start time was used as a substitute. For those patients for whom the total operative time times were recorded but surgical times were missing, an estimated time was calculated based on the average time difference between OR entry and surgery start time, and between surgical end time and OR. For this minority of patients, a mean additional time of 37 ± 7 min was added prior to the start of the surgery or after the time in the operating room, and 15 ± 6 min was added to the end surgical time, resulting in a mean total additional time of 52 ± 13 min.

Cochlear implantation SD and TORT were compared between both pediatric (≤ 18 years of age) and adult (> 18 years of age) implantees, as well as between unilateral, bilateral and revision CI with or without the assistance of a resident.

At our teaching institution, typically residents in their fourth post-graduate year complete a four-month rotation through the Otology/Neurotology service. In addition, comparisons were made between years of the procedure, primary as compared to revision surgery, and the relative complexity of the surgical procedure (existence or absence of cochlear ossification or malformed inner ear).

2.4

Data analysis

Data from the chart review were collected and entered into an Excel file, and imported into a statistical program (SPSS 20) for analysis. Both parametric and nonparametric statistics were used, as appropriate. Statistical analysis was done using the t-test for comparison of means, the Mann–Whitney test for comparison of median when appropriate and the one-way ANOVA and p-values for Tukey’s multiple comparison procedure. Simple linear regression was used to assess the correlation between SD, TORT and the other variables. Criterion for statistical significance was set at p ≤ 0.05, two-tailed.