Interferometric coupling of the Keck telescopes with single-mode fibers.

Here we report successful interferometric coupling of two large telescopes with single-mode fibers. Interference fringes were obtained in the 2- to 2.3-micrometer wavelength range on the star 107 Herculis by using the two Keck 10-meter telescopes, each feeding their common interferometric focus with 300 meters of single-mode fibers. This experiment demonstrates the potential of fibers for future kilometric arrays of telescopes and is the first step toward the 'OHANA (Optical Hawaiian Array for Nanoradian Astronomy) interferometer at the Mauna Kea observatory in Hawaii. It opens the way to sensitive optical imagers with resolutions below 1 milli-arc second. Our experimental setup can be directly extended to large telescopes separated by many hundreds of meters.

Discontinuous appendiceal involvement in ulcerative colitis: pathology and clinical correlation.

Continuous mucosal involvement from the rectum proximally is one of the hallmarks of ulcerative colitis. However, recent pathologic series report appendiceal ulcerative colitis in the presence of a histologically normal cecum, representing a "skip" lesion. The clinical significance of this finding has not been established. Eighty patients, 54 males and 26 females, average age 37.9 years (range 14 to 82 years) who underwent proctocolectomy for ulcerative colitis from January 1990 to September 1995 were examined to determine the rate of discontinuous appendiceal involvement. Excluded were 12 patients with prior appendectomy and 11 with fibrotic obliteration of the appendiceal lumen. Of the remaining 57 patients, seven (12.3%) had clear appendiceal involvement in the presence of a histologically normal cecum. These seven patients clinically were indistinguishable from the 50 patients without skip involvement of the appendix in terms of age at surgery, pretreatment medications, type of surgery, interval from diagnosis to definitive procedure, complications, functional results, and clinical course. Discontinuous appendiceal involvement was found in 12.3% of patients undergoing proctocolectomy for ulcerative colitis, and clinically these patients behave as those without this feature.

Long-term survival after treatment of malignant colonic polyps.

PURPOSE: This study was designed to evaluate the long-term outcome and survival of patients treated for malignant colonic polyps. METHODS: A retrospective review of 15,975 cases of colonoscopies with 8,685 endoscopic polypectomies performed between 1972 and 1990 was undertaken. In 65 patients, the polypectomy specimens contained invasive carcinoma. Six patients were excluded (follow-up, <6 months). Polyp data, operative findings, and follow-up on the remaining 59 patients were recorded. RESULTS: Malignant polyps were found in 35 males and 24 females who had an average age of 64 (range, 39-81) years. Follow-up ranged from 12 to 202 (mean, 90) months. Tumor differentiation was poor in one and well or moderately differentiated in 58 patients. Positive or indeterminate margins were found in 13 patients. Thirty-seven (63 percent) patients were managed with polypectomy and surveillance. Four of these (with rectal tumors) also had an additional local excision for questionable margins. One recurrence was noted in a patient who refused surgery, which was recommended because of indeterminate margins. Twenty-two patients (37 percent) underwent colectomy. Indications included Haggitt Level 3 or 4 invasion (19), inadequate margins (7), patient preference (1), and poor differentiation (1). Residual disease was found in colectomy specimens of three patients (14 percent). There were no cancer-related deaths in either treatment group. Life table analysis demonstrated a five-year survival of 82 percent for the colectomy group and 95 percent for the polypectomy group (P = 0.15). CONCLUSION: Treatment of patients with malignant polyps must be individualized based on evolving criteria. Patients in whom polypectomy margins are inadequate should undergo colectomy. With appropriate selection criteria, patients selected for colectomy had a five-year survival rate similar to the rate of those treated by polypectomy alone.

Treatment of colorectal and ileoanal anastomotic sinuses.

PURPOSE: This study is designed to describe a technique and report results for treating low anastomotic sinuses. METHODS: Restorative proctocolectomy and complicated low anterior resections were protected with diverting loop ileostomy. Contrast enemas identified anastomotic problems before ileostomy closure. Pouch-anal or colorectal anastomotic sinuses that failed to resolve with observation were treated before intestinal continuity was restored. With the patient receiving regional or general anesthesia, a rigid proctoscope or anoscope was used to identify the sinus opening. The common wall between the sinus and the bowel lumen was divided under direct vision with laparoscopic cautery scissors, and the sinus cavity was debrided with a suction cautery wand placed through the scope. RESULTS: Six patients with anastomotic sinuses have received outpatient treatment in the described manner during the past two years. Four patients had restorative proctocolectomies for ulcerative colitis, and two had low anastomosis for rectal cancer. Three patients presented with pelvic sepsis before the contrast study; the remainder were asymptomatic. Division of anastomotic sinus was performed one to eight months after diagnosis of the sinus. Following division, anastomotic cavities resolved in five patients by 1 month and in one patient by 12 months. In these six patients, there was one dilatable anastomotic stricture but no other anastomotic complications at follow-up 5 to 16 (mean, 9.2) months after sinus division. CONCLUSION: When used in conjunction with fecal diversion, sinus unroofing by division of the common wall between the sinus and bowel lumen treats low pelvic sinuses.

Outpatient bowel preparation for elective colon resection.

To determine the safety and cost-effectiveness of outpatient preoperative bowel preparation with polyethylene glycol-electrolyte lavage solution, we retrospectively analyzed 726 cases of colectomy done by colon and rectal surgeons between July 1987 and July 1991. Included were 319 patients who had elective segmental or total abdominal colectomy with primary anastomosis. Patients who required protective proximal stoma were excluded. Patients requiring emergency surgery, colostomy closure, and restorative proctocolectomy were excluded. Patients were separated into two groups equally matched by age, sex, procedure done, and comorbidity: 145 had bowel preparation as outpatients and 174 as inpatients. Both groups had similar numbers of days hospitalized, days receiving nothing by mouth, and days requiring nasogastric intubation or gastrostomy tube, as well as similar postoperative complications. There was one wound infection, one anastomotic leak, and one death in each group. Cost of outpatient preparation was approximately $40. Cost of inpatient preparation, including a semiprivate room, was approximately $400. Outpatient preparation with polyethylene glycol-electrolyte lavage solution and oral antibiotics before elective colon resection can be done with equivalent safety and at a substantial cost savings.

Predictive value of technetium Tc 99m-labeled red blood cell scintigraphy for positive angiogram in massive lower gastrointestinal hemorrhage.

PURPOSE: This study was performed to evaluate whether the time interval from injection of technetium Tc 99m (99mTc)-labeled red blood cells to the time of a radionuclide "blush" (positive scan) can be used to improve the efficacy in predicting a positive angiogram. METHOD: A retrospective review revealed 160 patients who received 99mTc-labeled red blood cell scintigraphy for evaluation of massive lower gastrointestinal hemorrhage between 1989 and 1994. Patients were included who demonstrated signs of shock on admission, had an initial decrease in hematocrit of > or = 6 percent, or required a minimum transfusion of two units of packed red blood cells. Scanning duration was 90 minutes, with imaging every 2 minutes. Time interval from injection to a positive scan was analyzed to determine predictability of a positive angiography. RESULTS: Of 160 patients, 86 demonstrated positive scans, of whom 47 underwent angiography. These 47 patients were divided into two groups according to scan results. Group 1 (n = 33) had immediate appearance of blush; Group 2 (n = 14) had blush after two minutes. In Group 1, 20 of 33 patients had a positive angiogram, yielding a positive predictive value of 60 percent (P = 0.033). Of the 14 patients with negative angiograms (13 from Group 1, and 1 with a negative scan), 6 had radiographic occlusion of the inferior mesenteric artery and 1 had spasm of the right colic artery, with scans that blushed in the respective distributions. Excluding these seven patients yielded a positive predictive value of 75 percent (P = 0.0072) for angiography. In patients with a delayed blush (Group 2), 13 of 14 had negative angiograms, yielding a negative predictive value of 93 percent (92 percent excluding those with nonvisualization of the inferior mesenteric artery). Twenty of 21 (95 percent) positive angiograms occurred in Group 1 patients. Of the 27 patients with negative angiograms, 13 were Group 2 patients. CONCLUSION: Patients with immediate blush on 99mTc-labeled red blood cell scintigraphy required urgent angiography. Patients with delayed blush have low angiographic yields. These data suggest that patients with delayed blush or negative scans may be observed and evaluated with colonoscopy.

Perineal repair of rectal prolapse.

Perineal approaches to the repair of rectal prolapse are frequently used in elderly or high-risk patients. These repairs have lower operative mortality and morbidity than intra-abdominal repairs but in general have higher recurrence rates. This study reviews our recent results with perineal prolapse repairs, briefly summarizes the literature, and discusses the available perineal operations. Eight patients (mean age 75 years) underwent surgical prolapse repair over an 18-month period. Treatment was by Altemeier's procedure (perineal rectosigmoidectomy) in 6 patients and Delorme's procedure in 2 patients. There were no operative mortalities, and an anastomotic dehiscence in 1 patient was managed nonoperatively. All patients with preoperative constipation improved and no patient reported worsening of continence. Surgical approaches from the perineum may be used in elderly and poor risk patients to treat rectal prolapse with low mortality and morbidity. These techniques have not adversely affected fecal continence and have improved symptoms of constipation with an acceptable rate of recurrence.

Surgical excision of large rectal villous adenomas.

Large villous tumors occur most frequently in the rectosigmoid and have a significant incidence of harboring a malignancy. The presence or absence of malignancy may be determined only by complete excision. Presence of invasive carcinoma on pathologic examination requires surgical intervention appropriate for that diagnosis. Recurrence depends on the technique used for tumor removal. It is highest for fulguration and local excision and lowest for operations that excise all or part of the rectum. Because most recurrences can be managed with local measures and the risk of malignancy in recurrences is relatively low, the procedure with which the tumor can be completely excised with the least morbidity should be used. Local excision with or without mucosal closure should be used as first-line surgical therapy whenever possible. It should be possible to manage most tumors in the mid and low rectum with this technique. For larger tumors and those tumors more proximal, it may be necessary to use snare cautery in combination with local excision or fulguration. Alternately, for some proximal rectal lesions the two-scope technique mentioned earlier may allow local excision. For circumferential or near circumferential tumors in the low to mid rectum, circumferential mucosectomy should be used. It has been used successfully for tumors involving the entire rectum down to the dentate line. Although this technique has a low recurrence rate, the rate of incontinence associated with it precludes its use in smaller tumors that are amenable to local excision. Transanal endoscopic microsurgery described by Beuss et al can produce good results. The authors have no experience with this technique. However, because of its expense, the need for specialized training, and the infrequency with which other transanal techniques are insufficient, we fail to see a significant role for its use. If use of this technique becomes more widespread, additional data regarding its value will become available. Posterior approaches offer no advantage for removal of tumors that can be excised by transanal techniques. Most tumors that require partial or complete rectal excision should be amenable to anterior or low anterior resection. Low anterior resection is a less morbid procedure with which most surgeons have a fairly extensive experience. For extremely large tumors that extend to the dentate line, coloanal anastomosis is appropriate. The functional results are acceptable compared with the alternative of abdominoperineal resection. Abdominoperineal resection should be reserved for those patients with a diagnosis of invasive carcinoma in whom a lesser procedure would not constitute adequate treatment.

Postpolypectomy colonic hemorrhage.

PURPOSE: This study was undertaken to evaluate the incidence, diagnostic methods, and treatment of hemorrhage occurring after colonoscopic polypectomy. METHODS: A retrospective chart review was conducted of 12,058 patients who underwent colonoscopy at an academic referral center between January 1989 and July 1993. Of these, 6,365 patients required polypectomies or biopsies. RESULTS: After these procedures, 13 patients (0.2 percent) developed lower gastrointestinal hemorrhage requiring hospitalization. All bleeding episodes occurred within 12 days of polypectomy or biopsy (mean = 8 days). Twelve patients (92 percent) underwent technetium-tagged red blood cell scintigraphy, which localized bleeding in four patients (31 percent). In the eight patients with normal scintigrams, hemorrhage did not recur, and no further evaluation was performed. Five patients (38 percent) underwent arteriography. Arteriogram was positive in two of four patients with positive scintigrams, and bleeding was controlled with selective vasopressin infusion. The fifth patient had arteriography without prior diagnostic studies because of massive hemorrhage; the bleeding site was identified and controlled with selective vasopressin infusion. Three patients had lower gastrointestinal endoscopy, with endoscopic identification of bleeding site in two patients, and endoscopic electrocautery controlled the bleeding in one patient. In the 13 patients with hemorrhage, cessation of bleeding occurred with intestinal rest and hydration in nine patients (69 percent), selective vasopressin infusion in three patients (23 percent), and endoscopic electrocautery in one patient (8 percent). Eight patients (62 percent) required blood transfusion with a mean of 4.8 units (excluding one patient on warfarin sodium who required 14 units of blood). No patient required surgical intervention. CONCLUSIONS: Incidence of hemorrhage after colonoscopic polypectomy or biopsy is low, and in our series, hemorrhage resolved without the need for surgical intervention. Management includes initial stabilization followed by diagnostic evaluation. Technetium-tagged red blood cell nuclear scintigraphy identifies ongoing bleeding and identifies patients in whom additional invasive procedures (arteriography lower gastrointestinal tract endoscopy) are warranted.

Colostomy closure. Ochsner Clinic experience.

PURPOSE: We retrospectively reviewed the records from our past five years of experience with colostomy closure at a large multispecialty hospital to determine postoperative morbidity. RESULTS: From March 1988 to April 1993, 46 patients underwent colostomy closure. Patients ranged in age from 24 to 87 (mean, 41.8) years, and 25 (54 percent) were women. Stomas had been created during emergency operations in 40 patients (87 percent); most operations (54 percent) were for complications of acute diverticulitis. Of the 46 procedures, 40 (87 percent) were end colostomies, and 6 were loop colostomies. Stomas were closed at a range of 11 to 1,357 days after creation (mean, 207 days; median, 116 days). Twenty-six patients (57 percent) underwent colostomy closure alone, and the remainder underwent additional procedures ranging from appendectomy to hepatic lobectomy. Duration of operations ranged from 1 to 9.5 (mean, 4.2) hours, and estimated blood loss averaged 400 ml. Overall hospital stay for closure was 6 to 62 (mean, 11.5) days. Inpatient complications occurred in 15 percent of patients, including congestive heart failure (2 percent), cerebrovascular accident (4 percent), pneumonia (2 percent), enterocutaneous fistula (2 percent), and pulmonary embolus with death (2 percent). The most common long-term complication was midline wound hernia, which occurred in 10 percent of surviving patients. Overall, complications occurred in 24 percent. CONCLUSIONS: Colostomy closure is a major operation; however, with good surgical judgement and technique, associated morbidity and mortality can be minimized.

Colon surveillance after colorectal cancer surgery.

PURPOSE: This study was performed to determine cost-effective colonoscopy guidelines for patients with prior colorectal adenocarcinoma. METHOD: A retrospective review was performed of patients who had been treated for colorectal adenocarcinoma and later underwent follow-up colonoscopy from 1984 to 1994. RESULTS: During this study period, 389 patients previously treated for colorectal adenocarcinoma underwent follow-up colonoscopy. All patients had perioperative colon evaluation for other neoplasms. Ages ranged from 26 to 89 (mean, 65.8) years, and 46.8 percent were female. Recurrent or metachronous cancer or a neoplastic polyp constituted a positive examination. Results of 389 first follow-up colonoscopies were compared with 259 second (66.6 percent), 165 third (42.4 percent), and 83 fourth (21.3 percent) follow-up examinations. Median interval between all colonoscopies was 13 months. Positive examination rates for the first two yearly examinations were 18.3 and 18.5 percent, respectively. Slightly lower, third-year and fourth-year positive examination rates were 16.4 and 14.5 percent, respectively. Four-year examinations yielded the following: first year--1 carcinoid, a new adenocarcinoma, and 100 polyps; second year--1 anastomotic recurrence and 68 polyps; third year --55 polyps; and fourth year--1 recurrent cancer and 17 polyps. CONCLUSIONS: These data suggest that 1) annual follow-up colonoscopy for two years after colorectal cancer surgery is beneficial for detecting recurrent and metachronous neoplasms and 2) the interval between subsequent examinations may be increased depending on the result of the most recent examination.

Fecal seepage and soiling: a problem of rectal sensation.

PURPOSE: To determine the physiologic alteration resulting in fecal seepage and soiling, results of anorectal manometric testing were evaluated in patients with varying degrees of fecal incontinence. METHODS: Anal manometric studies performed on 170 patients with fecal incontinence were reviewed. Results of their studies, including mean resting pressure, maximum resting pressure, maximum squeezing pressure, minimum rectal sensory volume, and minimum volume at which reflex relaxation first occurs, were compared with those of 35 control group subjects with normal fecal continence. Manometric studies were performed using a four-channel, water-perfused catheter. Incontinent patients were divided into three groups based on presenting complaints: complete incontinence (incontinence of gas and liquid and solid stool), partial incontinence (incontinence of gas and liquid), and seepage and soiling (incontinence of small amounts of liquid and solid stool without immediate awareness). RESULTS: Resting pressures were significantly lower in complete incontinence, partial incontinence, and seepage and soiling groups than in the controls (P < 0.001). Resting pressures of the complete incontinence group were also significantly lower than those of the partial incontinence and seepage and soiling groups (P = 0.03). Squeezing pressures were lower for both the complete incontinence and partial incontinence groups than for those in the control group (P < 0.001) and in the seepage and soiling group, which did not differ significantly from controls. The minimum rectal sensory volume was greater in all incontinent groups than in controls (P < 0.001). Sensory volume of the seepage and soiling group was significantly greater than that of the complete incontinence and partial incontinence groups (P < 0.01). The difference between sensory volume and the volume producing reflex relaxation was greatest in the seepage and soiling group and differed from that of the partial incontinence and control groups. CONCLUSIONS: These findings suggest that the mechanism of incontinence is different in seepage and soiling patients and involves a dyssynergy of rectal sensation and anal relaxation. Patients with the pattern of seepage and soiling may be successfully treated with stool bulking agents (e.g., psyllium or bran).

Colonoscopic follow-up of adenomas and colorectal cancer.

Increasing experience with colonoscopy has altered recommendations for the frequency of follow-up surveillance examinations for adenomatous polyps and colorectal cancer. Current recommendations include a follow-up colonoscopy at 1 year for patients with more than two adenomatous or highly suggestive polyps and after curative surgery for colorectal cancer. Other patients can safely receive a follow-up colonoscopy at longer intervals of 3 years. Published data and a review of the Ochsner Clinic experience are presented to support these recommendations.

Ulcerative colitis: surgical indications and alternatives.

Ulcerative colitis is a surgically curable mucosal disease of the colon and rectum. Optimal management of this chronic condition requires close coordination between the patient, surgeon, and primary care provider or gastroenterologist. Knowledge of surgical indications and the operative alternatives available helps to individualize therapy. Acute and chronic indications for surgery and the five surgical methods currently in use are described.

Reconstitution of intestinal continuity after extended left colectomy.

We wish to reintroduce an infrequently employed technique to re-establish intestinal continuity after extended resection of the left colon, transverse colon, and distal ascending colon. It involves bringing the proximal ascending colonic stump through the distal ileal mesenteric defect to reach the distal rectal stump in a tensionless fashion.

Mucinous carcinoma--just another colon cancer?

The significance of mucinous carcinoma has been controversial since first described by Parham in 1923. Previous reports have suggested that mucinous tumors affect young patients, involve the more proximal colon, are more advanced at diagnosis, and have a poorer prognosis than nonmucinous colon carcinoma. More recent reports have refuted these results. In an effort to clarify the significance of mucinous histology, a retrospective review of cases of invasive colon cancer treated at the Ochsner Clinic between 1982 and 1985 was undertaken. Mucinous adenocarcinoma, as defined by > or = 50 percent mucin, was found in 52 patients. During the same period, 343 nonmucinous adenocarcinomas were resected. The mean age, distribution within the colon, stage at diagnosis, and survival of mucinous carcinoma patients were compared with those with nonmucinous tumors. Mucinous tumors presented at a statistically significant more advanced stage (38 percent vs. 22 percent Dukes C lesions; P < 0.01). No significant differences were seen in age at presentation, distribution within the colon, or stage-for-stage survival when the entire group was analyzed. Mucinous carcinomas of the rectum occurred at an advanced stage more frequently (P < 0.05) than nonmucinous rectal carcinomas and had a markedly worse five-year survival (11 percent vs. 57 percent; P < 0.002).

Ogilvie's syndrome: colonoscopic decompression and analysis of predisposing factors.

Forty-eight cases of Ogilvie's syndrome, colonic pseudo-obstruction, presenting between 1983 and 1989 were retrospectively reviewed to assess the results of colonoscopic decompression and to identify potential etiologic factors. Three patients had spontaneous resolution with medical treatment. Forty-five patients required 60 colonoscopic decompressions: 38 (84 percent) were successfully treated using colonoscopy; five (11 percent) required an operation; and two died within 48 hours of colonoscopy from medical causes. No complications or deaths were the result of colonoscopy. Twenty-nine patients (64 percent) were successfully treated with a single colonoscopy. One-third of patients required serial decompressions. Average cecal diameter in patients with successful colonoscopic decompression was 12.4 cm but was larger for patients requiring more than one colonoscopy (13.3 cm) and for those who failed colonoscopic therapy (13.4 cm). The spine or retroperitoneum had been traumatized or manipulated in 52 percent of patients. Patients with Ogilvie's syndrome were being treated with narcotics (56 percent), H-2 blockers (52 percent), phenothiazines (42 percent), calcium-channel blockers (27 percent), steroids (23 percent), tricyclic antidepressants (15 percent), and epidural analgesics (6 percent) at diagnosis. Electrolyte abnormalities included hypocalcemia (63 percent), hyponatremia (38 percent), hypokalemia (29 percent), hypomagnesemia (21 percent), and hypophosphatemia (19 percent). Colonoscopic decompression in Ogilvie's syndrome is safe and effective management. Multiple pharmacologic and metabolic factors, as well as spinal and retroperitoneal trauma, appear to alter autonomic regulation of colonic function, resulting in colonic pseudo-obstruction.

Rectal carcinoids: the most frequent carcinoid tumor.

One hundred seventy patients with gastrointestinal carcinoid tumors were treated at Ochsner Clinic from 1958 to 1990. Ninety-four rectal carcinoid tumors were diagnosed and treated during this time. Carcinoid tumors of the rectum represented the most frequent primary site (55 percent), followed by carcinoids of the ileum (12 percent), appendix (12 percent), colon (6 percent), stomach (6 percent), jejunum (2 percent), pancreas (2 percent), and other (5 percent). One-half of rectal carcinoids were discovered during anorectal examination of asymptomatic patients. The remainder were found primarily by examination of patients for symptoms of benign anorectal conditions. The diagnosis of rectal carcinoid was made at the time of initial examination in 61 patients. This allowed definitive treatment in a single session by local excision and fulguration in 48 patients. The remainder were treated by repeat biopsy and fulguration (25 patients) or by transanal excision (12 patients). Overall, 85 carcinoid tumors of the rectum measuring less than 2 cm were treated by local excision and fulguration or by transanal excision, with an average five-year follow-up. There were no local recurrences. Ten patients with metastasizing rectal carcinoids averaging 4 cm were treated. All were symptomatic at presentation and fared poorly despite radical surgery. Three were alive at three years but only one survived five years. At our institution, rectal carcinoids were the most frequently detected carcinoid tumor. Small carcinoids of the rectum were adequately treated by local excision and fulguration or by transanal excision, with no local recurrence. The true incidence of rectal carcinoids is detected only with careful and complete rectal examination of the asymptomatic screening population by experienced surgeons. With more widespread screening of the well population, rectal carcinoids may become recognized as the most frequent human carcinoid tumor.

Diminutive colonic polyps: an indication for colonoscopy.

A prospective study investigated the significance of solitary diminutive colonic polyps discovered during screening flexible sigmoidoscopy. Eighty-two patients with a solitary diminutive polyp (less than or equal to 5 mm) underwent colonoscopy after cold biopsy of the index polyp. Of the patients with adenomatous index polyps, 42.5 percent had proximal neoplastic polyps. Of the patients with hyperplastic index polyps, proximal neoplastic polyps were found in 38.9 percent. These data suggest that diminutive polyps identified during flexible sigmoidoscopy, whether adenomatous or hyperplastic, place the patient in the intermediate risk group for colorectal neoplasia. We recommend that any patient with polyps seen during screening sigmoidoscopy, regardless of histopathology, should undergo colonoscopy.