Identifying and reducing errors with surgical simulation.

The major determinant of a patient's safety and outcome is the skill and judgment of the surgeon. While knowledge base and decision processing are evaluated during residency, technical skills-which are at the core of the profession-are not evaluated. Innovative state of the art simulation devices that train both surgical tasks and skills, without risk to patients, should allow for the detection and analysis of errors and "near misses". Studies have validated the use of a sophisticated endoscopic sinus surgery simulator (ES3) for training residents on a procedural basis. Assessments are proceeding as to whether the integration of a comprehensive ES3 training programme into the residency curriculum will have long term effects on surgical performance and patient outcomes. Using various otolaryngology residencies, subjects are exposed to mentored training on the ES3 as well as to minimally invasive trainers such as the MIST-VR. Technical errors are identified and quantified on the simulator and intraoperatively. Through a web based database, individual performance can be compared against a national standard. An upgraded version of the ES3 will be developed which will support patient specific anatomical models. This advance will allow study of the effects of simulated rehearsal of patient specific procedures (mission rehearsal) on patient outcomes and surgical errors during the actual procedure. The information gained from these studies will help usher in the next generation of surgical simulators that are anticipated to have significant impact on patient safety.

Phase I/II trial of outpatient docetaxel, cisplatin, 5-fluorouracil, leucovorin (opTPFL) as induction for squamous cell carcinoma of the head and neck (SCCHN).

The purpose of this study was to establish the maximum tolerated dose (MTD) of docetaxel in an outpatient docetaxel (T), cisplatin (P), 5-fluorouracil (5-FU) (F), and leucovorin (L) (opTPFL) regimen and to obtain preliminary assessment of opTPFL efficacy. Thirty-four patients with stage III or IV squamous cell carcinoma of the head and neck were treated with opTPFL. Docetaxel was escalated from 60 to 95 mg/m(2) in combination with 100 mg/m(2) cisplatin intravenous bolus, and 2,800 mg/m(2) 5-FU continuous infusion and 2,000 mg/m(2) leucovorin continuous infusion with prophylactic growth factors and antibiotics. Patients who achieved a complete (CR) or partial (PR) response to three cycles received definitive twice-daily radiation therapy. A total of 97 cycles were administered to 34 patients. The major acute toxicities were neutropenia and mucositis. The MTD of docetaxel was 90 mg/m(2) . Seventy-seven of 97 cycles of were administered on an outpatient basis. The overall clinical response rate to opTPFL was 94%, with 44% CRs and 50% PRs. The MTD of opTPFL is 90 mg/m(2) docetaxel. Outpatient administration of opTPFL is tolerable, feasible, and does not alter the ability to administer definitive radiation therapy on schedule.

Peripheral eosinophilia in the diagnosis of chronic rhinosinusitis.

PURPOSE: To determine the relationship between peripheral blood eosinophilia and chronic rhinosinusitis. MATERIALS AND METHODS: A retrospective review was conducted of consecutive operative cases during 1 calendar year. The preoperative complete blood count (CBC) were tabulated for three groups of patients: those undergoing endoscopic sinus surgery, those undergoing septoplasty with turbinate reduction alone, and a nonrhinologic control group. Statistical analysis was performed to determine differences in the components of the CBC among these three groups of patients and to identify significant associations between abnormal peripheral eosinophil counts and these diagnoses. RESULTS: A total of 87, 32, and 92 patients were identified for the endoscopic sinus surgery (ESS), septoplasty, and control groups, respectively. Significant differences in the percentages of eosinophils, lymphocytes, and neutrophils were noted among the three groups (P <.05). Comparison among groups indicated that ESS patients had significantly higher percent peripheral eosinophilia when compared with both the control group and septoplasty group (P <.001 and P =.010, respectively); no significant difference was noted between the septoplasty group and the control group (P =.627). The sensitivity and specificity of the peripheral eosinophil count for chronic sinusitis were 49.4% and 84.7%, respectively. CONCLUSIONS: The peripheral eosinophil count in chronic sinusitis is elevated compared with both a nonrhinologic control group and a group of patients with septal deviation. Furthermore, abnormally elevated eosinophil counts are associated with chronic sinusitis but not chronic rhinitis alone. However, this association is not strong enough to be used in the diagnosis of chronic sinusitis because of poor sensitivity.

Benchmarks for mortality, morbidity, and length of stay for head and neck surgical procedures.

OBJECTIVE: To determine benchmarks and factors that influence morbidity, mortality, and length of stay (LOS) for head and neck surgical procedures. METHODS: A specific database for head and neck surgical procedures was extracted from the National Hospital Data Survey database for 1995 through 1997. Records of inpatient admissions for patients undergoing head and neck surgery were examined to determine demographics, incidence of medical complications, mortality, and LOS. Data were statistically examined for the influence of medical complications on mortality and LOS. RESULTS: A total of 3932 patients underwent head and neck procedures. The overall medical morbidity and mortality rates were 5.65% and 2.98%, respectively. The presence of a major medical complication increased the odds of death by 5.65 (P<.001). Postoperative pneumonia was the most common medical complication (3.26%) and was associated with a mortality rate of 10.94% (odds ratio for mortality, 4.4). Acute myocardial infarction and stroke were rare (combined incidence, 1.86%) and were not statistically associated with increased mortality. Procedures that involved the esophagus carried the highest mortality rate (8.38%). The overall mean LOS was 6.15 days. This increased to 17.7 days when a major medical complication occurred (P<.001). Increasing age was associated with increased rates of medical complications and mortality (P<.001). CONCLUSIONS: Medical complications in patients undergoing head and neck surgical procedures are associated with increased mortality rates and longer LOS. Mortality rates in head and neck surgery are low but may be improved by preventing medical complications.

Assessment of the airway in obstructive sleep apnea syndrome with 3-dimensional airway computed tomography.

OBJECTIVE: The goal was to evaluate 3-dimensional airway CT for upper airway assessment in obstructive sleep apnea syndrome (OSAS). DESIGN: Airway CT was obtained and 3-dimensional airway models were constructed prospectively for 40 patients with OSAS and 10 controls. Airway dimensions were correlated with polysomnography, and comparison was made between patients with and without OSAS. RESULTS: OSAS patients had a mean respiratory distress index of 51.9 events per hour. The mean minimum cross-sectional area (XSA) in the neutral position was 67.1 mm(2). Minimum XSA decreased in both the inspiratory and expiratory phases to 16.3 mm(2) and 15.0 mm(2), respectively (P<0.001). Complete airway obstruction occurred in 1 or more phases of respiration in 28 patients. Neither airway XSA nor length of obstruction correlated with sleep apnea parameters. No statistically significant differences in airway dimensions were found between OSAS and control patients. CONCLUSIONS: Airway CT demonstrates dynamic airway obstruction in OSAS but does not correlate well with clinically important disease parameters.

Phase II trial of docetaxel, cisplatin, fluorouracil, and leucovorin as induction for squamous cell carcinoma of the head and neck.

PURPOSE: To evaluate the toxicity and efficacy of a 4-day regimen of docetaxel, cisplatin, fluorouracil, and leucovorin (TPFL4) in patients with locoregionally advanced squamous cell carcinoma of the head and neck (SCCHN). PATIENTS AND METHODS: Thirty previously untreated patients with stage III or IV SCCHN and Eastern Cooperative Oncology Group functional status of 2 or less were treated with TPFL4. Postchemotherapy support included prophylactic growth factors and antibiotics. Patients who achieved a complete response (CR) or partial response (PR) to three cycles of TPFL4 received definitive twice-daily radiation therapy. The primary end points were toxicity and response to TPFL4. RESULTS: Eighty-five cycles were administered to 30 patients. The major acute toxicities to TPFL4 were mucositis and nausea. One patient died of neutropenic sepsis during therapy. Additional major toxicities were neutropenia, anorexia, nephropathy, neuropathy, and diarrhea. Fourteen percent of all cycles were associated with hospitalization for toxicity. The overall clinical response rate to TPFL4 was 93%, with 63% CRs and 30% PRs. Primary tumor site clinical and pathologic response rates were 93% and 68%, respectively. CONCLUSION: TPFL4 has an acceptable toxicity profile in good-performance-status patients. Modification of the 5-day TPFL regimen (TPFL5: shorter chemotherapy infusion time, earlier intervention with growth factors and antibiotics) led to fewer episodes of febrile neutropenia and hospitalization. Response rates to TPFL justify further evaluation of combinations of these agents in the context of formal clinical trials.

Virtual laryngoscopy.

Virtual endoscopy enables computer-generated 3-dimensional visualization of a cavity by reconstructing 2-dimensional computed tomographic or magnetic resonance data. The technique has been used experimentally to study the colon, bronchi, ears, and other structures. Here, virtual laryngoscopies were created from the cross-sectional image data of 3 patients. The cases represented a normal airway, a squamous cell carcinoma of the glottic fold, and a posterior glottic stenosis. These reconstructions included extraluminal anatomy that is not typical of current virtual endoscopic techniques. The 2-dimensional computed tomographic and magnetic resonance images of the patients underwent post-processing for 3-dimensional reconstruction. The resulting models were imported into an experimental virtual endoscopy program for 1) airway lumen generation and 2) interactive viewing. Though they could not be used for biopsy, the virtual laryngoscopies provided, in a noninvasive fashion, good simulation of endoscopy. Virtual endoscopy also gave the added benefits of the ability to assess the transmural extent of disease and view the airway distal to areas of luminal compromise. This technology may well provide clinical benefit in preoperative planning, staging, and intraprocedural guidance for head and neck disease and merits further study.

MRI monitoring of laser ablation using optical flow.

The optical flow method is used for visualizing and quantifying the dynamics of tissue changes observed by MRI during thermal ablations. An approach was implemented for parallel two-dimensional optical flow calculations including the replacement of spurious velocities. Velocity magnitude results were found to be accurate in low-noise cases in tests using series of synthetic images. Optical flow results are presented from thermal ablation experiments utilizing a homogeneous polyacrylamide gel phantom and heterogeneous rabbit liver tissue in vivo, exhibiting heating and cooling with the accompanying quantitative characterization of the dilation and contraction of the thermally affected region. Results demonstrate that optical flow is capable of noninvasive real-time monitoring and control of interstitial laser therapy (ILT).

Computer-assisted three-dimensional reconstruction of head and neck tumors.

OBJECTIVE: Because head and neck tumors reside in a complex area, having a three-dimensional (3-D) model of the patient's unique anatomical features may assist in the delineation of pathology. The authors describe a new computer technique of 3-D anatomical reconstruction from two-dimensional computed tomography (CT) and magnetic resonance (MR) data and discuss how it represents a step forward in the continuing evolution of 3-D imaging. STUDY DESIGN: The authors selected three patients with solitary head and neck tumors and reconstructed their anatomy in a 3-D format for study. The tumors represented locations in the nose and central skull base (patient 1), temporal bone (patient 2), and neck (patient 3). MATERIALS AND METHODS: MR and CT images from the individual patients were electronically transferred to workstations in the Surgical Planning Laboratory of the authors' institution. Registration (or fusion) was carried out between the MR and CT images. The desired anatomic components underwent segmentation (identification and isolation). Assembly of the segmented images was performed and the resulting structures were integrated to produce a 3-D model. RESULTS: 3-D models of the following were constructed and displayed in an interactive format on high-capacity computer workstations: 1) a skull base sarcoma with extension into the nasopharynx and nose; 2) an acoustic neuroma with internal auditory canal involvement; and 3) a metastatic recurrence of a tongue base squamous cell carcinoma in the posterior triangle of the right side of the neck with extension to the skull base. CONCLUSION: The authors' Surgical Planning Laboratory has developed a 3-D reconstruction technique that has several new features. The models provided a very good 3-D interactive representation of the tumors and patient anatomy. The need now exists to develop this method of 3-D reconstruction of head and neck tumors for potential applications in treatment, research, and medical education.

Endoscopic sinus surgery with magnetic resonance imaging guidance: initial patient experience.

We report the first endoscopic surgeries performed with patients under general anesthesia using intraoperative guidance with MRI. The procedures were experimental and intended to test (1) the unusual working environment of a unique new "open-configuration" MRI unit for head and neck surgery, and (2) real-time image guidance. Twelve patients underwent endoscopic sinus surgery while under general anesthesia in a new open MRI unit that provides the surgeon with access to the patient while imaging is performed. Eleven patients had chronic sinusitis (eight of them had bilateral disease), and one had a right nasoethmoid and antral tumor. All 12 surgeries were performed without complications. Both the endoscopic view and the MRI scans were available at the surgical field. The image plane was surgeon controlled, and the MRI updated images in as little as 14 seconds. MRI provided adequate visualization of both the disease and the related anatomy and allowed the surgeon to navigate during the procedure. The intraoperative data reflect the tissue changes during surgery and provide optimum feedback for surgical guidance. Although the operating environment poses some limitations, it has become apparent that intraoperative MRI has a role in the treatment of head and neck disorders and warrants further study.

MR-guided endoscopic sinus surgery.

We describe an interactive, intraoperative imaging-guided method for performing endoscopic sinus surgery (ESS) within a vertically open MR system. The procedure was performed with intraoperative imaging using a 0.5-T magnet with a 56-cm vertical gap. Interactive control of imaging planes was accomplished by optical tracking with two infrared light-emitting diodes mounted on an aspirator probe. The probe's position defined the location of the orthogonal imaging planes. Twelve patients with varying degrees of sinus disease underwent ESS with MR imaging guidance. Patients had acute and chronic sinusitis, nasal polyposis causing airway obstruction, or tumor requiring tissue biopsy. All procedures were performed with the patients under general anesthesia. The integration of endoscopy with optical tracking and intraoperative interactive imaging allowed localization of anatomic landmarks during ESS. No complications were encountered.

Computer-augmented endoscopic sinus surgery.

Review of current literature on computer-augmented endoscopic sinus surgery reflects a sustained interest in developing a role for available frameless stereotactic technologies to provide image guidance for the surgeon. The interest is motivated by the prospect of increased intraoperative patient safety in that image guidance assists the surgeon in navigating through diseased or surgically revised complex anatomy. The authors feel that in time the technique will enable a new level of efficiency in endoscopic sinus surgery.

Virtual otoscopy.

Imaging techniques assist the surgeon in diagnosis of disease, surgical planning, and providing image guidance during surgery. Endoscopy has the drawback of being a minimally invasive procedure and limiting visualization to the inner surface of the lumen. Ultrasound, CT, and MR imaging show volumes of tissue beyond the lumen wall; however, their planar, two-dimensional representations require mental reconstruction of anatomic structures, which often proves difficult with the small, complex structures within the temporal bone. To improve three-dimensional visualization of the inner ear, we successfully completed a virtual model that can be displayed as a contiguous, three-dimensional luminal view, known as virtual otoscopy, which emulates traditional endoscopy. A concomitant global view and a view of the related CT slice adds a distinct advantage in the presentation and study of this complex organ. Advances in computer and software technology may overcome the time and cost factors that, at present, limit widespread use of virtual otoscopy. Overall, virtual otoscopy stands as a promising new visualization technique for elucidation of the middle ear, inner ear, and temporal bone structures.

Interactive magnetic resonance imaging-guided biopsy in the head and neck: initial patient experience.

Because of its excellent soft tissue resolution, magnetic resonance imaging (MRI) can optimize image guidance for interventional and surgical procedures. Notably, needle biopsy of head and neck lesions has been used for years, deeper lesions often requiring some form of image guidance. The closed space of diagnostic MRI scanners proves cumbersome for intervention. The authors report on the first head and neck image-guided biopsies performed in a new, investigational "open configuration" intraoperative MRI scanner. Vertical space between the scanner's upright coils gives access to the patient while imaging; image acquisition is as fast as 2 sec/image. Biopsies were performed on seven patients (parotid, parapharyngeal space, second cervical vertebra); five specimens were diagnostic. Both general anesthesia and intravenous sedation were used. The procedures were without complications. Imaging provided definition of anatomy to direct needle placement. Access to the patient allowed for both percutaneous and transoral approaches. The environment of the open magnet is well suited for biopsy of the head and neck, and near real-time intraoperative MRI has promise for guiding more complex head and neck procedures. Further study should optimize the quality of the images and the interactibility of localization and targeting and fully utilize MRI's three-dimensional imaging capabilities.

Compatible instrumentation for intraoperative MRI: expanding resources.

Steadfast progress has been made from biopsy to surgery with interventional MRI (iMRI). Such image-guided interventions require specialized instrumentation due to the unusual elements of the MR environment. Suppliers/manufacturers of MR-compatible instrumentation were few in 1994, but now there are more than 50. We present fundamental issues of MR compatibility and a list of known suppliers/manufacturers.

MRI of laser-induced interstitial thermal injury in an in vivo animal liver model with histologic correlation.

Laser-induced interstitial thermal therapy (LITT) is a preferred method of minimally invasive therapy. MRI is a noninvasive method by which to monitor the thermal effects of LITT. To properly control such effects, changes in MRI parameters during and after LITT should be correlated with changes in the tissue. T1-weighted fast spin echo (FSE) MRI (1 image/10 seconds) at 1.5 T monitored LITT in vivo in rabbit liver (n = 6) using an interstitial bare delivery fiber (600-microm diameter; 3.0 W; 1,064 nm; 150 seconds). During laser irradiation, MRI signal intensity decreased around the fiber tip; after irradiation, this hypointensity proved reversible and permanent lesions were evident. The lesions had hyperintense margins that were brighter than surrounding normal tissue (P < .001); the tissue in these bright regions was mapped to tissue necrosis characterized by the presence of thermally damaged ghost red blood cells amid generally normal hepatocytes. T1-FSE identified the spatial extent of the LITT lesions.

Anatomic location of the tongue base neurovascular bundle.

Knowledge of the location of the hypoglossal/lingual artery neurovascular bundle (HLNVB) is essential in performing tongue base resections for neoplasm and for obstructive sleep apnea. Transoral and transcervical resections of the tongue base may be performed with greater exposure and certainty when the relationship of the HLNVB to local landmarks is understood; knowledge of the HLNVB allows resection of a larger amount of contralateral tongue base during partial glossectomy without violating the contralateral remnant tongue's blood supply. Ten cadaver heads were dissected to determine the position of the HLNVB with respect to soft tissue and bony landmarks at the tongue base. Our results indicate the position of the tongue base HLNVB is significantly inferior and lateral, that is, 2.7 cm inferior and 1.6 cm lateral to the foramen cecum, 0.9 cm superior to the hyoid bone, and 2.2 cm medial to the mandible. This inferolateral location allows the potential for aggressive tongue base resection without neurovascular compromise.