The Role of Choledochoscopy: The Eternal Problem of How to Remove a CBD Stone.

BACKGROUND: Identifying and surgically removing bile duct calculi is challenging and critical in order to provide good patient outcomes. The history of this surgical pursuit since the introduction of anesthesia is both enlightening and fascinating. METHODS: A systematic review of the literature was conducted to identify the techniques and technology used to remove bile duct calculi. RESULTS: All bile duct surgical exploration advances have involved creation of tools to look within the bile duct and extract stones. The Hopkin's rod lens system was a major breakthrough in light and image transmission. However, flexible endoscope technology added the ability to maneuver better within the bile duct as well as apply the technology via laparoscopy enabling laparoscopic bile duct exploration. CONCLUSION: Digital, image enhanced, distal tipped chip flexible endoscopes have significantly improved the surgeons' ability to see within the bile duct, improving the efficiency and ease of stone visualization and removal from both the most proximal and distal ends of the bile duct.

Concomitant dual intravascular and subcutaneous microsurgical implantation of xenograft tissue in a rodent model for evaluation of structural degeneration.

INTRODUCTION: An economical animal model to study xenograft tissue degeneration and calcification and the durability of biological vascular patch material and bioprosthetic valve leaflets is desirable. OBJECTIVE: A cost-effective model to analyze xenograft degeneration, calcification, immunologic reaction, and anticalcification treatment was developed. Furthermore, a technique for implant into the vascular lumen of the abdominal aorta in rats is presented. METHODS: Twelve Lewis rats were used as recipients. The microsurgical procedure was performed using a high-definition optical system. Anesthesia was induced and maintained with isoflurane inhalation. The suprarenal and infrarenal portion of the abdominal aorta was isolated, the abdominal aorta was cross-clamped, and a 4-mm square portion of the abdominal aorta was removed. Subsequently, a complementary-sized piece of porcine or bovine glutaraldehyde-fixed bioprosthetic valve leaflet tissue was sutured as a patch in the abdominal aorta. RESULTS: The mean operating time was 45 ± 10 minutes and the mean ischemic time was 25 ± 5 minutes. Early and 3-month survivals were 100%. One rat had intraoperative bleeding. No paralysis or thrombosis was observed. CONCLUSION: Feasibility and reproducibility of removing a portion of the abdominal aorta and replacing it with a patch of xenograft tissue was demonstrated in a rodent model with 100% survival at 3 months. Concomitant dual intravascular and subcutaneous microsurgical implantation of xenograft tissue in a small-animal (rat) model is a cost-effective approach for investigation of xenograft tissue degeneration.

High definition optical system for microsurgical heterotopic heart transplantation in rats.

BACKGROUND: Clinical and experimental cardiovascular surgery as well as other surgical disciplines may require visualization and manipulation of small anatomic structures. A high-definition optical system was developed for magnification and illumination as an alternative to surgical loupes or a traditional operating microscope. MATERIALS AND METHODS: A video telescopic optical imaging system that provided a high-definition and magnification of the surgical field was used for visualization of small anatomic structures and as an aid to the performance of small vessel anastomoses in a series of 10 heterotopic heart transplants (HHTx) in rats. RESULTS: The video telescopic optical system was easy to manipulate and comfortable to use, and provided high-definition images for magnification of anatomic structures while performing microvascular cardiac surgery in a small animal model of HHTx in rats. Fatigue and neck problems for the surgeon were reduced. CONCLUSIONS: The video telescopic imaging system provided high definition and magnification of the surgical field, and was used for visualization of small anatomic structures and as an aid to the performance of small vessel anastomoses. The system is an alternative to surgical loupes or a traditional operating microscope, and was used for the first time in microvascular cardiac surgery in a rat HHTx model.

Performance differences in laparoscopic surgical skills between true high-definition and three-chip CCD video systems.

BACKGROUND: Laparoscopic surgery requires surgeons to rely on visual clues for discrimination among differing tissues and for depth of field on a two-dimensional screen. High definition (HD) provides a superior image. If there is a measurable advantage with HD television (TV), the increase in the cost of the technology would be justified. METHODS: A digital three-chip CCD camera with a standard monitor (SD system) and a true HD camera (1,080 pixels) with a 16:9-ratio HD monitor (HD system) were compared in clinical and laboratory settings. Three experiments were performed: (1) subjective visual evaluation of the HD and SD systems during actual surgical cases, (2) subjective visual evaluation in a controlled laboratory surgical setting with simultaneous parallel recording, and (3) three laparoscopic surgical task evaluations in a laboratory setting, namely, task A (metric analysis of participants on the surgical simulator), task B (simple eye-hand coordination performance), and task C (knot tying). RESULTS: All 53 participants subjectively evaluated HD as superior to SD in the laboratory setting and during actual surgery. In task B, there was no significant difference between SD and HD (dominant hand: p = 0.19; nondominant hand: p = 0.07). In task C, the knot-tying time was significantly less when performed with HD (mean, 173 +/- 84 s vs 214 +/- 107 s; p = 0.003). Most importantly, subjects with less skill (more documented time required in the basic module on a surgical simulator) improved significantly in the knot-tying task with the HD system (R = 0.631; p = 0.005). CONCLUSION: All the participants preferred HD to SD. High definition significantly improved laparoscopic knot tying, which requires precise depth perception, proving that HD is more than just a pretty picture.

Seeing is believing: the importance of video laryngoscopy in teaching and in managing the difficult airway.

Of the several million patients who undergo surgery in North America annually, a large proportion undergo intubation of the trachea. In approximately 90% of these patients, the endotracheal tube is introduced using a traditional laryngoscope with a battery in the handle and a small bulb near the tip of the blade. This bulb provides a limited and often dim view of the glottic structures. In about 10% of cases, the patient is intubated using a flexible fiberoptic intubating scope. The authors have developed a video laryngoscope that preserves the standard blade configuration with a modified handle. A 3-mm image light guide is built into the blade, replacing the bulb. A small TV camera with an incorporated light bundle is inserted into the handle. A wide-angle panoramic view of the upper airway anatomy is displayed on a TV screen, which can be positioned at a convenient working distance. The use of a TV monitor is a well-accepted standard during minimally invasive surgical procedures.

Operating videoscope for microlaryngeal surgery.

For operative laryngoscopy, a laryngoscope is introduced into the anesthetized patient's mouth for exploration of the larynx and vocal cords. To improve the vision, a binocular microscope is positioned between the operator and the laryngoscope. This interferes, to some degree, with the introduction of instruments, particularly if the surgeon is using bimanual manipulation. In the case of lengthy operations, a fatigue or stress factor can be troublesome to the operator. The authors developed a video laryngoscope using standard blades. An angulated telescope attached to a TV camera was introduced in the top portion of the blade. An enlarged image from the anatomy was produced and viewed from a convenient distance. The manipulations are unobstructed, and simultaneous records can be obtained. It is the method of choice for teaching. The operative laryngoscope is less cumbersome and supersedes the microscope for viewing the endolarynx. This new technique was used successfully in 532 cases.

Assessment of the efficacy of endoscopy in pituitary adenoma resection.

OBJECTIVE: To obtain objective evidence that the use of endoscopy in the surgical management of pituitary tumors improves intraoperative visualization and significantly impacts operative outcomes. DESIGN: Case series of pituitary adenomas treated surgically by endoscope-assisted microscopic resection. SETTING: University-affiliated tertiary care medical center. PATIENTS: Consecutive sample of 9 patients referred for surgical management of pituitary adenoma. INTERVENTIONS: Each patient underwent transseptal transsphenoidal microscopic tumor resection. The procedure was modified by the use of intrasellar endoscopy as an adjunctive imaging modality. Following complete microscopic resection of tumor, rigid 0 degrees and 30 degrees 4.0-mm endoscopes were used to conduct a final survey of the sellar and parasellar spaces. Residual tumor fragments identified during this endoscopic examination were removed. OUTCOME MEASURES: Endoscopes were thought to have a significant impact on surgical therapy in cases where residual tumor that was not detected microscopically was identified and removed during endoscopic examination. Analysis of each case included correlation between intraoperative findings and retrospective review of dictated operative reports and intraoperative videotape. RESULTS: Three of the patients with macroadenoma (33% of total, 43% of macroadenoma cases) had tumor fragments that were only identified and removed endoscopically. CONCLUSIONS: Endoscopy provides distinct advantages over microscopy in imaging intrasellar and parasellar structures during pituitary tumor resection. These data support the numerous anecdotal accounts of the usefulness of pituitary endoscopy and are consistent with the small amount of objective evidence offered on the subject. Arch Otolaryngol Head Neck Surg. 2000;126:1487-1490

Endoscope-assisted microvascular decompression of the trigeminal nerve.

Twenty-one patients with classic symptoms of trigeminal neuralgia underwent microvascular decompression of the trigeminal nerve through a retrosigmoid approach to the cerebellopontine angle. Endoscopy was used as an adjunctive imaging modality to microscopy. Specifically, endoscopes were used to confirm nerve-vessel conflicts identified by the microscope and to reveal others that escaped microscopic survey. Endoscopes were also used to assess the adequacy of the decompression performed microscopically. A total of 51 nerve-vessel conflicts were identified and treated, 14 of which were discovered only after endoscopy. Additionally, in 5 patients endoscopic examination of the surgical intervention demonstrated that further maneuvers were required to completely decompress the nerve. These results highlight the value of endoscopy in the diagnosis and therapy of cranial nerve pathology in the posterior fossa.

Endoscopic transglabellar approach to the anterior fossa and paranasal sinuses.

Historically, surgical management of tumors of the anterior cranial fossa with extension to the paranasal sinuses has been problematic. Wide exposure of these lesions has traditionally called for prolonged retraction of the frontal lobes or potentially disfiguring transfacial approaches, subjecting patients to undesirable neurological and cosmetic morbidity. With the introduction of progressively less invasive procedures, however, intracranial tumors with craniofacial involvement have become amenable to en bloc resection with a minimum of deleterious consequences. Increasing experience with endoscopy as an imaging modality in intracranial and extracranial surgery has led to the adaptation of endoscopic techniques to this setting. We have used an entirely endoscopic transglabellar approach to the anterior fossa to resect suprasellar tumors in two patients. The use of endoscopy allowed thorough visualization of all critical structures at the paramedian skull base without the need for a bicoronal scalp flap, bifrontal osteotomies, or brain retraction. Both lesions were resected in their entirety with no perioperative complications and with acceptable cosmetic results. These cases demonstrate how the application of endoscopy to surgery of the anterior skull base and craniofacial skeleton can eliminate the need for excessively invasive techniques without compromising surgical success.

Endoscopic skull base surgery I: a new animal model for pituitary surgery.

Endoscopy has emerged as a new means to perform minimally invasive surgery of the skull base. Specifically, endoscopic techniques and instruments can be used to safely and effectively approach and resect tumors of the pituitary gland in humans. No animal model currently exists to serve as a template upon which to refine and develop endoscopic surgical technique in this region of the anatomy. We operated on two purpose-bred Hampshire-Yorkshire-Duroc hybrid swine to demonstrate the application of endoscopy to pituitary surgery. Based upon similar anatomical relationships in humans and swine between the oropharynx, nasopharynx, and skull base, we used a transoral, transpalatal approach to access the vomer of the swine. Under endoscopic exposure, we resected the vomer, entered the sphenoid sinus, and then resected the sphenoid septum, sella turcica, and adenohypophysis. Clear visualization of the pituitary, hypophyseal stalk, cavernous sinuses, and carotid prominences was achieved and documented with digital photography. Benefits and limitations of the technique were noted. These results have pertinent implications both for the study of the surgical anatomy of the swine craniofacial skeleton, and for future development of endoscopic surgical manipulation of the skull base.

Endoscopic pituitary surgery: an in vivo model for transnasal transsphenoidal hypophysectomy.

The transseptal transsphenoidal approach to surgical intervention of the pituitary gland has been described for decades. Its gradual acceptance as the standard of therapy is indicative of general trends toward less invasive means of managing intracranial surgical disease. The evolution of the technique has coincided with advances in medical technology, including the introductions of intraoperative fluoroscopy and operative microscopy. Current progress in the field of endoscopy promises to further this evolution: endoscopic telescopes and instruments have improved on the optical and technical limitations of the microscope and require an even less invasive approach to the sella. To test the benefits and limitations of the endoscope in performing transnasal transsphenoidal hypophysectomy in an in vivo model, we operated on two live anesthetized pigs using 4.0-mm 0- and 30-degree 18-cm long endoscopes. The long lengths of the pig snouts precluded a transnasal approach to the sella; however, we were able to use the endoscopes to explore the sphenoid sinus, sella turcica, and parasellar regions via a transoral exposure. Digital images of the relevant skull base anatomy were captured. The benefits and limitations of the technique were noted and compared with our experience with microscopy in transsphenoidal hypophysectomy in humans.

Miniature laparoscopy: quo vadis? The basic parameters of image relay and display systems.

BACKGROUND: Endoscopy created a new epoch in gynecology and general surgery. After a decade of learning experiences and expansion of laparoscopic surgery in a variety of areas, the need to further miniaturize the endosurgical approach surfaced. This, however, requires a better knowledge about the tools that surgeons must or wish to employ in minimal access surgery. For miniaturization, the quality of the image on the TV monitor is critical. METHODS: We examined two miniature optical systems: the quartz-fiber (2.0-2.2 mm) and the rod-lens (3.3-mm) relay technologies. RESULTS: The smaller quartz telescope image was found to be brighter but lacking in other important features that are important in diagnosis and surgical manipulations. CONCLUSIONS: Because the detail, clarity, and the color display affect decision making and the course taken, the brand of telescope has to be selected according to the particular application. By following this guideline, a number of diagnostic and therapeutic procedures can be performed using smaller instruments with the patient under local anesthesia with sedation or under general anesthesia in an outpatient setting.

Endoscopic skull base surgery II: a new animal model for surgery of the posterior fossa.

The field of skull base surgery has been influenced by a general philosophy that currently exists in modern surgical practice favoring less invasive means of managing surgical disease. Adapting techniques developed by general surgeons and other surgical subspecialists, skull base surgeons are now experimenting with endoscopy to resect tumors, manage vascular lesions, and manipulate critical intracranial structures. Lesions formerly requiring significant soft tissue dissection and craniotomy for exposure are now potentially amenable to treatment via a keyhole approach. As in other surgical specialties, however, a reliable animal model is necessary for experimentation with and development of new endoscopic techniques in the skull base. The swine provides just such a model, primarily due to craniofacial and skull base relationships that are analogous to humans. We have focused on the posterior skull base of the swine in this experiment: Via a retrosigmoid craniotomy we opened the dura of the posterior fossa and used endoscopes to visualize and manipulate the critical structures in this area. The cerebellum and midbrain were appreciated, as were cranial nerves V, VII, VIII, IX, X, and XI. Blood vessels on the surface of the midbrain were also identified. This experience further supports the use of the swine as an appropriate animal model for endoscopic skull base surgery.