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PubMed1992

Contribution of localized calcium deposits to dissection after angioplasty. An observational study using intravascular ultrasound.

BACKGROUND: Atherosclerotic plaque fracture and dissection of the arterial wall are frequent concomitants of the balloon angioplasty process. The composition and morphology of plaque within the vessel may be critical in determining the extent of plaque fracture and dissection during balloon angioplasty. To examine this potential association in the clinical setting, we studied patients with intravascular ultrasound imaging after balloon angioplasty. METHODS AND RESULTS: Forty-one patients were studied with intravascular ultrasound after angioplasty in both peripheral and coronary arteries. Ultrasound images representing the target lesion cross section were digitized, stored on computer, and analyzed off-line. The presence of intralesional calcium and the relative size of dissection for each lesion was computed. Thirty-one patients (76%) had ultrasound evidence of significant dissection or plaque fracture immediately after balloon dilation. In 23 of 31 (74%) of the lesions, the ultrasound scans showed significant localized calcium deposits within the plaque substance. In 87% of these cases, the dissections were adjacent to the calcific portion of the vessel wall. In addition, the relative size of dissections referenced to the neolumen area were significantly larger (p less than or equal to 0.002) in the calcified vessels (27.5 +/- 12.3%) compared with the size of the dissections in lesions without calcium (11.2 +/- 5.8%). CONCLUSIONS: The presence of calcium within the vessel wall appeared to be significantly associated with both the location and size of the dissected tissue arm from the vessel wall. These data suggest that localized calcium deposits have a direct role in promoting dissection, presumably by increasing shear stresses within the plaque.

Angioplasty, Balloon, Coronary↗

PubMed1996

Novel biochemical diagnostic method for aortic dissection. Results of a prospective study using an immunoassay of smooth muscle myosin heavy chain.

BACKGROUND: Aortic dissection is one of the most common aortic catastrophes. Although newer diagnostic methods as exemplified by image diagnostic techniques have greatly improved the diagnosis of aortic dissection, the diagnosis is still frequently missed today because the signs and symptoms of the disease are at times obscure. A reliable biochemical diagnostic method for aortic dissection would be beneficial. METHODS AND RESULTS: A novel biochemical diagnostic method for diagnosis of aortic dissection was developed that uses an immunoassay of monoclonal antibodies to smooth muscle myosin heavy chain. A prospective study was conducted to ascertain the usefulness of the method in the diagnosis of aortic dissection. Twenty-seven patients with aortic dissection admitted within the first 24 hours after onset were enrolled. Serial assay of serum smooth muscle myosin heavy chain showed significant elevations within the first 24 hours after onset of aortic dissection, with levels exceeding 10 ng/mL, with subsequent rapid reductions. The sensitivity of the assay within the first 12 hours was 90% with a specificity of 97%. Analysis of 65 patients with acute myocardial infarction showed that the method could accurately differentiate myocardial infarction from aortic dissection. CONCLUSIONS: The immunoassay of serum smooth muscle myosin heavy chain is a rapid and reliable biochemical method in the diagnosis of aortic dissection. The potential use of the method in clinical medicine is promising.

Aged↗

PubMed2004

Virtual colon dissection with CT colonography compared with axial interpretation and conventional colonoscopy: preliminary results.

OBJECTIVE: The aim of this study was to determine whether a new virtual colon dissection 3D visualization technique for CT colonography has a shorter analysis time and better sensitivity for detection of colonic polyps than interpretation of axial CT images. SUBJECTS AND METHODS. CT colonography was performed in 22 patients using 4-MDCT followed by conventional colonoscopy on the same day. The CT colonography data sets were analyzed by virtual colon dissection, which virtually bisects and unfolds the colon along its longitudinal axis to inspect the inner colonic surface for polyps. The same CT data sets were independently evaluated using axial interpretation. All data sets were independently interpreted by two radiologists in a blinded manner. RESULTS: Conventional colonoscopy revealed 31 colonic lesions in 20 patients. Twenty two of the lesions were smaller than 10 mm; nine were 10 mm or larger. Two of the original 22 patients were excluded, one because of residual stool and fluid and the other because of an impassable stenosing rectal wall cancer. For virtual colon dissection, the per-lesion sensitivity was 42% for observer 1 and 68% for observer 2; for axial interpretation, the respective sensitivities were 48% and 61%. For polyps 10 mm or larger, the respective sensitivities were 67% and 89% for virtual colon dissection and 89% and 100% for axial interpretation. The average time for reconstruction and analysis of virtual colon dissection was 36.8 min versus 29.2 min for axial images. Virtual colon dissection was feasible in both the supine and the prone positions in 45.5% of colonic segments, in either the supine or the prone position in 24.5%, and in neither position in 30% of segments. CONCLUSION: Although virtual colon dissection may facilitate detection of colonic polyps in isolated cases, its detection rate is not superior to axial interpretation, which is mainly attributable to failed rendering of insufficiently distended colonic segments or regions with residual feces. Virtual colon dissection is also the more time-consuming of the two procedures. With further improvement of path-finding and image segmentation, however, virtual colon dissection has the potential to be a useful interpretation tool for CT colonography.

Adult↗

PubMed2002

[Strategy of neck dissection in parotid cancer].

We conducted definitive surgery on 45 patients with untreated primary parotid cancer from 1975 to 1995, and evaluated methods of neck dissection and results of treatment. All 14 with clinical neck lymph node metastasis underwent ipsilateral radical neck dissection and only 1 developed neck lymph node recurrence at the peripheral dissected site. Of 31 patients without clinical neck lymph node metastasis, 27 of 19 of 36 with high-grade malignancy and 12 of 24 with T3 or T4 did not undergo prophylactic neck dissection and developed latent neck lymph node metastasis in 2 cases (7.4%). Whereas in most cases we achieved good control of the primary site but neck lymph node recurrences occurred, recurrent sites were observed all around the ipsilateral neck and prognosis were very poor if neck dissection was conducted as secondary treatment. Although histopathological diagnosis was considered feasible for predicting occult neck lymph node metastasis, correct diagnostic with fine needle aspiration cytology revealed only 21.8%. Pathological positive lymph nodes in 15 patients who underwent neck dissection were detected all over (level I to V) the ipsilateral neck and the recurrent positive rate at level II was 100%. Based on the above results, we conclude that (1) in cases with neck lymph node metastasis in preoperative evaluation, ipsilateral radical neck dissection is mandated, and (2) in cases without neck lymph node metastasis, prophylactic neck dissection is not usually needed. When pathological results of frozen section from intraoperative jugulodigastric nodal sampling are positive, ipsilateral radical neck dissection is mandated.

Adolescent↗

PubMedDate not supplied

[Cervical dissection in laryngeal cancer: our experience of 15 years].

A retrospective study was made of surgery with cervical dissection in 640 patients with laryngeal carcinoma treated from 1976 to 1991. Cervical dissection was carried out in 386 of 640 patients with laryngeal carcinoma treated surgically. Of a total of 496 cervical dissections performed, there were 173 unilateral functional, 88 bilateral functional, 67 unilateral block, 13 bilateral block, and 27 bilateral block dissections with contralateral functional dissection. The relations between tumor stage (T) and nodal involvement (N), type of dissection and T, type of dissection and N, laryngeal surgery and neck dissection, clinical and histological N, N+ and histologic type, extracapsular spread, number of recurrences, and their relation with T and N, and the relation between N+ and type of neck dissection were studied.

Adult↗

PubMed1996

Therapeutic options and results for the management of minimally invasive carcinoma of the breast: influence of axillary dissection for treatment of T1a and T1b lesions.

BACKGROUND: Axillary dissection has maintained a role of primacy for the surgical therapy of invasive carcinoma of the breast for many years. More recently, early (T1) minimally invasive carcinoma of the breast has been diagnosed with increasing frequency, and the necessity of axillary dissection for sampling purposes in these small tumors has been questioned, based primarily on the finding of low rates of axillary metastases. STUDY DESIGN: The Rhode Island State Tumor Registry records of 1,126 patients with T1a or T1b tumors were examined to assess the effect of axillary dissection on patient outcome. These data span 9 years (1985 to 1992) with a median follow-up duration of 64 months. Five-year overall, disease-free, and breast cancer-specific (determinate) survival were determined according to treatment modality. Axillary node positivity was calculated for patients with minimally invasive carcinoma of the breast who underwent axillary dissection. Multivariate statistical methods were used to provide adjustment for known confounding prognostic variables. RESULTS: Omission of axillary dissection occurred in 157 cases and correlated with reductions in overall, disease-free, and breast cancer-specific survival (p < .001 in all cases). Nodal status significantly influenced disease-free survival in minimally invasive carcinoma of the breast (90 percent node-negative compared with 76 percent node-positive, p = .02). Nodal positivity was evident in 18.2 percent of patients undergoing axillary dissection for minimally invasive carcinoma of the breast (9.8 percent for T1a, 19.4 percent for T1b, p = .01). In multivariate analysis, the performance of axillary dissection with breast conservation or modified radical mastectomy were independent predictors of overall survival, as well as disease-free and breast cancer-specific survival. CONCLUSIONS: A significant number of patients with small (less than or equal to 1 cm) invasive tumors of the breast will have axillary metastases at the time of diagnosis. Omission of axillary dissection in these patients was associated with significant impairment of overall, disease-free, and breast cancer-specific survival. Axillary dissection should continue to be a standard approach for the surgical therapy of all patients with invasive carcinoma of the breast, regardless of tumor size.

Adenocarcinoma, Mucinous↗

PubMed2002

Duplex scan findings in patients with spontaneous cervical artery dissections.

AIM: to report duplex scan findings in patients with spontaneous internal carotid artery (ICA) or vertebral artery (VA) dissection. MATERIAL AND METHODS: the records of 24 patients (13 males and 11 females, median age 48 years [range 25-68 years]) with spontaneous extracranial ICA dissection (n=20) or VA dissection (n=4), identified between January 1995 and December 1999, were retrospectively analysed. RESULTS: four different abnormal flow patterns were observed in patients with ICA dissection: (a) absence of flow (15%), (b) staccato flow (50%), (c) reduced flow velocity (25%) and, (d) stenotic flow (10%). B-mode ultrasound showed a homogenous echolucent lesion in eight patients and a double lumen in two. Staccato flow along the entire ICA was observed in only four patients without verified dissection during the study period. In the four patients with VA dissection, duplex scanning demonstrated staccato flow in three and reversed low-amplitude pulsatile flow in one. CONCLUSION: duplex scanning is an important noninvasive diagnostic modality in patients with cervical artery dissection. Staccato flow along the extracranial ICA strongly indicates the presence of spontaneous ICA dissection.

Adult↗

PubMed2003

Spinal manipulative therapy is an independent risk factor for vertebral artery dissection.

OBJECTIVE: To determine whether spinal manipulative therapy (SMT) is an independent risk factor for cervical artery dissection. METHODS: Using a nested case-control design, the authors reviewed all patients under age 60 with cervical arterial dissection (n = 151) and ischemic stroke or TIA from between 1995 and 2000 at two academic stroke centers. Controls (n = 306) were selected to match cases by sex and within age strata. Cases and controls were solicited by mail, and respondents were interviewed using a structured questionnaire. The medical records of interviewed patients were reviewed by two blinded neurologists to confirm that the patient had stroke or TIA and to determine whether there was evidence of arterial dissection. RESULTS: After interview and blinded chart review, 51 patients with dissection (mean age 41 +/- 10 years; 59% female) and 100 control patients (44 +/- 9 years; 58% female) were studied. In univariate analysis, patients with dissection were more likely to have had SMT within 30 days (14% vs 3%, p = 0.032), to have had neck or head pain preceding stroke or TIA (76% vs 40%, p < 0.001), and to be current consumers of alcohol (76% vs 57%, p = 0.021). In multivariate analysis, vertebral artery dissections were independently associated with SMT within 30 days (OR 6.62, 95% CI 1.4 to 30) and pain before stroke/TIA (OR 3.76, 95% CI 1.3 to 11). CONCLUSIONS: This case-controlled study of the influence of SMT and cervical arterial dissection shows that SMT is independently associated with vertebral arterial dissection, even after controlling for neck pain. Patients undergoing SMT should be consented for risk of stroke or vascular injury from the procedure. A significant increase in neck pain following spinal manipulative therapy warrants immediate medical evaluation.

Adult↗

PubMed2006

Diagnostic accuracy of transesophageal echocardiography, helical computed tomography, and magnetic resonance imaging for suspected thoracic aortic dissection: systematic review and meta-analysis.

BACKGROUND: Patients with suspected thoracic aortic dissection require early and accurate diagnosis. Aortography has been replaced by less invasive imaging techniques including transesophageal echocardiography (TEE), helical computed tomography (CT), and magnetic resonance imaging (MRI); however, accuracies have varied from trial to trial, and which imaging technique should be applied to which risk population remains unclear. We systematically reviewed the diagnostic accuracy of these imaging techniques in patients with suspected thoracic aortic dissection. METHODS: Published English-language reports on the diagnosis of thoracic aortic dissection by TEE, helical CT, or MRI were identified from electronic databases. Sensitivity, specificity, and positive and negative likelihood ratios were pooled in a random-effects model. RESULTS: Sixteen studies involving a total of 1139 patients were selected. Pooled sensitivity (98%-100%) and specificity (95%-98%) were comparable between imaging techniques. The pooled positive likelihood ratio appeared to be higher for MRI (positive likelihood ratio, 25.3; 95% confidence interval, 11.1-57.1) than for TEE (14.1; 6.0-33.2) or helical CT (13.9; 4.2-46.0). If a patient had shown a 50% pretest probability of thoracic aortic dissection (high risk), he or she had a 93% to 96% posttest probability of thoracic aortic dissection following a positive result of each imaging test. If a patient had a 5% pretest probability of thoracic aortic dissection (low risk), he or she had a 0.1% to 0.3% posttest probability of thoracic aortic dissection following a negative result of each imaging test. CONCLUSION: All 3 imaging techniques, ie, TEE, helical CT, and MRI, yield clinically equally reliable diagnostic values for confirming or ruling out thoracic aortic dissection.

Aortic Dissection↗

PubMed2000

The role of cervical lymphadenectomy after aggressive concomitant chemoradiotherapy: the feasibility of selective neck dissection.

OBJECTIVES: To evaluate the necessity, technical feasibility, and complication rate of neck dissection performed on patients with head and neck cancer after 5 cycles of concomitant chemoradiotherapy (CRT) and to justify a selective neck dissection (SND) approach and define the optimal timing of post-CRT neck dissection. DESIGN AND SETTING: Retrospective analysis in an academic university medical center. PATIENTS: Sixty-nine eligible patients with advanced (stage III and IV) head and neck cancer who have undergone 1 of 4 CRT protocols. Patients ranged in age from 36 to 75 years, and surgical procedures were performed over a 4-year period. Follow-up ranged from 6 to 64 months. INTERVENTION: Neck dissection (most commonly unilateral SND) performed within 5 to 17 weeks after CRT completion. MAIN OUTCOME MEASURES: Complication rate and incidence of positive pathology (viable cancer) in pathologic neck dissection specimens. RESULTS: Seven (10%) of 69 patients developed wound healing complications, 4 (6%) of whom required surgical intervention for ultimate closure. There were no wound infections. Other complications occurred in 11 (16%) of 69 patients and included need for tracheotomy, nerve transection and paresis, and permanent hypocalcemia. Twenty-four (35%) of 69 patients revealed microscopic residual disease. Ten (50%) of 20 patients with N3 neck disease had positive pathology, whereas 14 (36%) of 39 patients with N2 disease had viable carcinoma in the dissection specimen (P =.09 by chi(2) analysis). There was no significant relation between radiologic complete response or partial response and residual microscopic cancer. In 1 patient, disease recurred in the neck after dissection. Mean follow-up time was 30.3 months. CONCLUSIONS: (1) Neck dissection for patients with N2 or greater neck disease after CRT is necessary to eradicate residual disease. (2) The complication rate of SND after CRT with hyperfractionated radiotherapy is low. (3) SNDs are technically feasible when performed within the "window" between the acute and chronic CRT injury (4-12 weeks). (4) SNDs, rather than more radical procedures, appear to be therapeutically appropriate in this group of patients because of the low incidence of disease recurrence in the neck.

Adult↗

PubMed2002

Microvascular reconstruction after previous neck dissection.

BACKGROUND: Microvascular reconstruction of defects in the head and neck is more challenging in patients who have undergone a previous neck dissection, owing to prior resection of potential cervical recipient blood vessels used for free flap perfusion. OBJECTIVE: To evaluate the reliability and safety of free flap reconstruction in patients with previous neck dissection. PATIENTS AND METHODS: Sixty free flaps were performed in 59 patients with a medical history of neck dissection for head and neck cancer. This included patients undergoing salvage surgery for recurrent cancer as well as patients undergoing secondary reconstruction of cancer surgery-related defects. Flap selection included 25 radial forearm flaps, 20 fibula flaps, 7 rectus abdominis flaps, 7 subscapular system flaps, and 1 iliac crest flap. RESULTS: Recipient vessels were used in the field of previous neck dissection in approximately half the patients with previous selective neck dissection, while contralateral recipient vessels were always used in patients with a history of modified radical or radical neck dissection. Vein grafts were not necessary in any cases. One arterial anastomosis that was created under excessive tension required urgent reoperation and revision, but there were no cases of free flap failure. CONCLUSIONS: Free flap reconstruction of the head and neck is highly successful in patients with a history of neck dissection, despite a relative paucity of potential cervical recipient blood vessels. Heavy reliance on free flaps with long vascular pedicles obviated the need to perform vein grafts in the present series, probably contributing to the absence of free flap failure. Previous neck dissection should not be considered a contraindication to microvascular reconstruction of the head and neck.

Adult↗

PubMed1999

Planned neck dissection as an adjunct to the management of patients with advanced neck disease treated with definitive radiotherapy: for some or for all?

BACKGROUND: Management of patients with head and neck carcinoma and advanced nodal disease is controversial. The purpose of this analysis was to evaluate the efficacy and toxicity of definitive radiotherapy followed by planned neck dissection in patients with bulky neck disease. MATERIALS AND METHODS: The records of 52 patients who were treated between 1989 and 1995 at the Peter MacCallum Cancer Institute with a planned neck dissection after radical radiotherapy were reviewed. All had advanced neck disease with one or more nodes >/=3 cm in maximum diameter, 94% being staged N2-3. The most common primary site was the oropharynx (56%). Sixty percent of patients had either T2 or T3 primaries and all were AJCC stage IV. Treatment consisted of high-dose radiotherapy to the primary and involved neck sites using various fractionation protocols followed by radical or modified radical neck dissection after confirmation of a complete response at the primary site. The median follow-up for living patients was 58 months (range 32-97). RESULTS: There were nine regional failures, of which three were outside the dissected neck, yielding a 5-year actuarial overall neck control rate of 83% and an in-field control rate of 88%. In-field control rates by neck stage were N1 3/3; N2 31/35; N3 11/13 and NX 1/1. There was only one in-field failure among 28 patients who had pathologically negative neck specimens compared with five in 24 patients with morphologic evidence of residual disease. Of the 24 patients with pathologically positive necks, 5 were long-term survivors and were probably cured by their surgery. Another 4 died of intercurrent disease without documented recurrence of their head and neck cancer. Ten patients recurred at their primary sites (5-year actuarial control 79%) and 8 developed distant metastases (5-year actuarial rate 20%). A total of 21 patients failed at one or more sites and none was salvaged. Five-year actuarial disease-free survival was 57% and overall survival 38%. Nine patients (17%) sustained significant complications following neck dissection. CONCLUSIONS: In patients with advanced neck disease who are treated primarily with radical radiotherapy, planned neck dissection provides excellent regional control and appears to cure a subset of patients. However, routine neck dissection adds significant morbidity to treatment and should ideally be avoided in those patients in whom surgery is either unnecessary (no residual tumor) or futile (unsalvageable disease recurrence outside the dissected neck). Based on our analysis and other recently reported series, we now recommend observing patients who have a complete response to high-dose radiotherapy (+/- chemotherapy). The ability of PET imaging to detect residual viable tumor in the head and neck or at distant sites is under investigation.

Adult↗

PubMed1996

Preclinical student reactions to dissection, death, and dying.

The objective of the present study was to determine the reactions of preclinical medical students to dissection; cognate issues. A questionnaire was administered to a class of 148 students; the stimulus items inquired about the frequency of mental and physical symptoms, causes of stress, degree of upset occasioned by dissection, previous encounters with death, mental preparedness at the commencement of the course, reactions to dissecting room activities, coping strategies, and the desirability of a course on death and dying. Nearly a quarter of the sample reported an increase in the frequency of mental and physical symptoms. A third of the students identified the dissecting room as a "very important" stressor. Only for female respondents were "dissecting room" and "great difficulty of work" significantly associated as causes of stress. Over three-quarters of the students were upset at the beginning of dissection and about a third remained disturbed after 101.5 hours. Sixty students had seen a dead body previously and 30 students had been bereaved within the 2 years preceding the study. However, neither prior exposure to a dead body nor bereavement was a safeguard against persistent upset by dissection. The initial reactions were mostly negative, but neutral and positive attitudes later supervened. The coping strategies cited did not suggest any significant distortion attributable to the unseemly origins of the cadavers. A compulsory formal course on death and dying during both preclinical and clinical stages was considered desirable by the majority of respondents, more for personal and clinical reasons than for dissection-related ones.

Adolescent↗

PubMed2004

Improved dissection efficiency in the human gross anatomy laboratory by the integration of computers and modern technology.

The need to increase the efficiency of dissection in the gross anatomy laboratory has been the driving force behind the technologic changes we have recently implemented. With the introduction of an integrated systems-based medical curriculum and a reduction in laboratory teaching hours, anatomy faculty at the University of North Texas Health Science Center (UNTHSC) developed a computer-based dissection manual to adjust to these curricular changes and time constraints. At each cadaver workstation, Apple iMac computers were added and a new dissection manual, running in a browser-based format, was installed. Within the text of the manual, anatomical structures required for dissection were linked to digital images from prosected materials; in addition, for each body system, the dissection manual included images from cross sections, radiographs, CT scans, and histology. Although we have placed a high priority on computerization of the anatomy laboratory, we remain strong advocates of the importance of cadaver dissection. It is our belief that the utilization of computers for dissection is a natural evolution of technology and fosters creative teaching strategies adapted for anatomy laboratories in the 21st century. Our strategy has significantly enhanced the independence and proficiency of our students, the efficiency of their dissection time, and the quality of laboratory instruction by the faculty.

Anatomy↗

PubMed2006

Efficacy of routine bilateral neck dissection in the management of the N0 neck in T1-T2 unilateral supraglottic cancer.

BACKGROUND: The treatment of the clinically negative (N0) neck in supraglottic laryngeal cancer continues to be an area of controversy. The aim of this study was to analyze the long-term efficacy of routine bilateral neck dissection compared with ipsilateral neck dissection in T1-T2 N0 lateral supraglottic carcinomas. METHODS: A retrospective review of 108 patients who underwent surgery for T1-T2 supraglottic squamous cell carcinoma was performed. Forty-eight had undergone ipsilateral functional neck dissection, and 60 had undergone bilateral functional neck dissections. None of these patients received adjuvant radiotherapy. RESULTS: No significant differences (p = .78) in regional recurrence were observed between the patients treated with bilateral neck dissection (13%) and those treated with ipsilateral neck dissection (17%). The 5-year survival rates were 73% and 80% for the patients who received a bilateral and ipsilateral neck dissection, respectively (p = .51). CONCLUSIONS: This study suggests that routine bilateral neck dissection may not be necessary in the surgical treatment of all supraglottic cancers.

Adult↗

PubMed2006

Role of neck dissection following concurrent chemoradiation for advanced head and neck carcinoma.

BACKGROUND: Our primary objective was to determine the role of neck dissection following concomitant chemoradiation (CRT) for advanced stage III-IV head and neck squamous cell carcinoma (HNSCC). METHODS: One hundred eighty-four patients with HNSCC treated with CRT were included. One hundred twenty-three patients reached a regional complete response (CR) after CRT and no neck dissection was performed. Forty-five patients among the 58 who reached a regional partial response (PR) underwent a neck dissection. RESULTS: Overall, regional CR rate after CRT was 68%. Patients who reached a regional CR (no neck dissection) had an overall neck recurrence rate of 5%. Patients with regional PR who underwent a neck dissection had a 7% neck recurrence rate. CONCLUSIONS: Patients with regional CR not followed by a neck dissection have a low rate of neck recurrence. Systematic neck dissection is not mandatory for patients with nodes less than 6 cm reaching a regional CR. For patients with nodes larger than 6 cm, no firm recommendation can be given because of the small number of patients in this series. If the regional response is incomplete, cervical dissection is warranted.

Adult↗

PubMed2004

Experimental application of pulsed Ho:YAG laser-induced liquid jet as a novel rigid neuroendoscopic dissection device.

BACKGROUND AND OBJECTIVES: Although water jet technology has been considered as a feasible neuroendoscopic dissection methodology because of its ability to perform selective tissue dissection without thermal damage, problems associated with continuous use of water and the ensuing fountain-effect-with catapulting of the tissue-could make water jets unsuitable for endoscopic use, in terms of safety and ease of handling. Therefore, the authors experimented with minimization of water usage during the application of a pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser-induced liquid jet (LILJ), while assuring the dissection quality and the controllability of a conventional water jet dissection device. We have developed the LILJ generator for use as a rigid neuroendoscope, discerned its mechanical behavior, and evaluated its dissection ability using the cadaveric rabbit ventricular wall. STUDY DESIGN/MATERIALS AND METHODS: The LILJ generator is incorporated into the tip of a stainless steel tube (length: 22 cm; internal diameter: 1.0 mm; external diameter: 1.4 mm), so that the device can be inserted into a commercial, rigid neuroendoscope. Briefly, the LILJ is generated by irradiating an internally supplied water column within the stainless steel tube using the pulsed Ho:YAG laser (wave length: 2.1 microm, pulse duration time: 350 microseconds) and is then ejected through the metal nozzle (internal diameter: 100 microm). The Ho:YAG laser pulse energy is conveyed through optical quartz fiber (core diameter: 400 microm), while cold water (5 degrees C) is internally supplied at a rate of 40 ml/hour. The relationship between laser energy (range: 40-433 mJ/pulse), standoff distance (defined as the distance between the tip of the optical fiber and the nozzle end; range: 10-30 mm), and the velocity, shape, pressure, and average volume of the ejected jet were analyzed by means of high-speed camera, PVDF needle hydrophone, and digital scale. The quality of the dissection plane, the preservation of blood vessels, and the penetration depth were evaluated using five fresh cadaveric rabbit ventricular walls, under neuroendoscopic vision. RESULTS: Jet velocity (7.0-19.6 m/second) and pressure (0.07-0.28 MPa) could be controlled by varying the laser energy, which determined the penetration depth in the cadaveric rabbit ventricular wall (0.07-1.30 mm/shot). The latter could be cut into desirable shapes-without thermal effects-under clear neuroendoscopic vision. The average volume of a single ejected jet could be confined to 0.42-1.52 microl/shot, and there was no accompanying generation of shock waves. Histological specimens revealed a sharp dissection plane and demonstrated that blood vessels of diameter over 100 microm could be preserved, without thermal damage. CONCLUSIONS: The present pulsed LILJ system holds promise as a safe and reliable dissection device for deployment in a rigid neuroendoscope.

Animals↗

PubMed2003

Surgical treatment of acute arch dissection.

OBJECTIVES: Acute type A arch dissections are rare and no consensus has been reached on their surgical treatment. We studied perioperative risk factors for mortality in arch dissection patients. METHODS: Between October 1995 and October 2001, 108 patients with acute type A dissection were operated on, of whom 16 had acute arch dissections. Their mean age was 58 +/- 9 (44-77). Surgery involved total arch replacement in 4, hemiarch replacement in 10, and intimal tear repair with pledgeted sutures and ascending aortic replacement in 2. RESULTS: One patient who underwent total arch replacement died intraoperatively due to bleeding. Both patients who underwent ascending aortic replacement and primary repair of arch tears died 2 days postoperatively, 1 due to bleeding, and the other due to multiorgan failure. In-hospital mortality was thus 18.75%, or 3 of 16. All 3 had cardiac tamponade preoperatively. The 13 survivors were discharged after a mean hospital stay of 11 +/- 6 days. Mean follow-up was 38 +/- 25 months, from 3 months to 6 years. One patient died due to graft infection 3 months postoperatively, but the remaining 12 remain in good condition. Univariate predictors of in-hospital mortality were the type of surgery (primary intimal tear repair) (p = 0.027) and preoperative cardiac tamponade (p = 0.007). CONCLUSION: Surgical treatment of acute type A-arch dissections can be done with reasonable mortality and mid-term survival comparable with those of other subgroups with acute type A dissection. As with series of arch dissections, our patient population is too small to draw specific conclusions, but our experience leads us to conclude that the sites of intimal tears should be resected in acute type A arch dissection.

Acute Disease↗