Targeting Epilepsy Through the Foremen Ovale: How Many Helical Needles are Needed?

Laser ablation of the hippocampus offers medically refractory epilepsy patients an alternative to invasive surgeries. Emerging commercial solutions deliver the ablator through a burr hole in the back of the head. We recently introduced a new access path through the foremen ovale, using a helical needle, which minimizes the amount of healthy brain tissue the needle must pass through on its way to the hippocampus, and also enables the needle to follow the medial axis of the hippocampus more closely. In this paper, we investigate whether helical needles should be designed and fabricated on a patient-specific basis as we had previously proposed, or whether a small collection of pre-defined needle shapes can apply across many patients. We propose a new optimization strategy to determine this needle set using patient data, and investigate the accuracy with which these needles can reach the the medial axis of the hippocampus. We find that three basic tube shapes (mirrored as necessary for left vs. right hippocampi) are all that is required, across 20 patient datasets (obtained from 10 patient CT scans), to reduce worst-case maximum error below 2 mm.

In vitro study and in vivo application of a reusable double-channel sphincterotome.

BACKGROUND AND STUDY AIMS: Therapeutic endoscopic retrograde cholangiopancreatography (ERCP) has been deemed to be a "cost-prohibitive" procedure, based upon the cumulative costs of one-time-use accessories and current reimbursement plans. One-time-use sphincterotomes comprise a significant component of that cost and, accordingly, we evaluated the disability and clinical usefulness of a recently introduced reusable double-channel sphincterotome. MATERIALS AND METHODS: We studied a reusable 6-Fr sphincterotome at baseline and following contamination with 10(6) Bacillus stearothermophilus. Reprocessing included a unique 30-minute ultrasonic cleaning step in lieu of manual cleaning, followed by steam sterilization. Parameters evaluated included sphincterotome function, electrical integrity, and our ability to sterilize the devices for three in vitro trials. In vivo studies included patient demographics and outcomes, procedural findings, and success rates, and the mean number of times the sphincterotome was used, functional grading at time of use, and reasons for sphincterotome malfunction. RESULTS: Ten out of ten sphincterotomes maintained form, function, and electrical integrity in vitro, and all cultures were negative after sterilization. In the initial in vivo study, ten sphincterotomes were used in 50 patients (mean, 5 uses) with a 94% success rate. Reasons for sphincterotome failure included leak or breakage of the accessory port in 70%, wire fracture in 10%, incorrect wire bow in 10%, and clogged injection port in 10%. Following reconfiguration of the insertion-port polymer, an additional ten sphincterotomes were used in 110 patients (mean, 11 uses). Mechanical failure occurred primarily at the wire-insertion port, resulting in progressive friction with reuse. There were neither electrical nor infectious complications associated with reuse. CONCLUSIONS: A reusable double-channel sphincterotome is available which can theoretically be reprocessed and sterilized without the manual cleaning step of the reprocessing process. Contingent upon both provider and patient, multiple reuse can be anticipated, and contingent upon purchase price and reprocessing costs, the potential for procedural cost savings is significant.

Reusable biopsy forceps: a prospective evaluation of cleaning, function, adequacy of tissue specimen, and durability.

BACKGROUND: Recent studies have indicated that reusable biopsy forceps remain contaminated after reprocessing and can only be used a mean of 12 to 25 times without malfunction. Because this contradicts traditional endoscopic practice, our study investigated the ability to sterilize a type of commercially available biopsy forceps and prospectively evaluated their function in vivo until malfunction and/or breakage. METHODS: Thirty reusable biopsy forceps were studied, 15 of which were contaminated for 5 trials each with 10(6) Bacillus stearothermophilus, and 15 of which were prospectively evaluated clinically over an 18-month period (9/98-3/00). Contaminated forceps were reprocessed by using a standard protocol and placed in a sterile bag containing soy broth. The latter was passed through a 0.2 micron filter and was subsequently cultured. In vivo data included biopsy site, size, adequacy, problems obtaining a biopsy specimen, and reasons for ultimate forceps failure. RESULTS: After contamination, all biopsy forceps yielded a heavy growth of B stearothermophilus. No forceps, including 5 that were piecemeal dismantled with a wire cutter, had residual bacteria after reprocessing. In the in vivo study, 1507 biopsy sessions were undertaken in 1339 procedures. Forceps were categorized as new or like-new in 1259 of 1339 (94%) procedures, some loss of function but usable in 72 of 1339 (5.4%), and inadequate function or broken at use in 8 of 1339 (0.6%). Histologically, 1501 specimen sets were adequate (99.6%) and mean specimen size was 2.7 +/- 0.1 mm. Mechanical problems were noted in only 38 of 1507 (3%) sessions to include such things as sticky forceps, and the mean number of uses to malfunction or breakage was 91 +/- 15 (SEM) (range 19-132). CONCLUSIONS: This reusable biopsy forceps can be sterilized and used a mean of 91 times with adequate tissue sampling. Mechanical problems were minor to time of breakage. Contingent on acquisition and reprocessing costs as well as the number of procedures performed, this reusable forceps has the potential for significant cost savings.

In vitro and in vivo evaluation of a reusable double-channel sphincterotome.

BACKGROUND: To date, one reusable, double-channel sphincterotome has been approved by the Food and Drug Administration in the United States. Whether this device can be reprocessed easily and whether it is more durable than currently manufactured disposable sphincterotomes are uncertain. METHODS: Thirty double-channel, 20 mm, braided-wire sphincterotomes approved for multiple uses were studied in vitro/in vivo with regard to durability and sterilization. A cost analysis of reusable, disposable, and reprocessed disposable sphincterotomes was also carried out. RESULTS: Three of 10 sphincterotomes evaluated in vitro broke after 3, 4, and 8 uses. Electrical integrity was preserved after 10 uses in the remaining sphincterotomes. Nine sphincterotomes remained functional for at least 3 uses, five for 6 uses, and one for 10 uses. Culture results after inoculation demonstrated contamination with surviving organisms after manual cleaning and no growth after ethylene oxide sterilization. Sixty-one procedures were performed in vivo using 20 sphincterotomes (mean number of uses 3.1). No evidence of procedurally related infection occurred with reuse. Cost per use of this reusable sphincterotome was calculated to be $62.98; it became cost effective after 2.2 and 7.9 uses when compared with disposable and reprocessed, disposable sphincterotomes, respectively. CONCLUSIONS: This reusable sphincterotome proved to be safe, easily sterilized, and electrically intact after repeated use. In vivo, however, a progressive loss of function limited the mean number of uses to 3.1. In settings that preclude reuse of reprocessed disposable accessories, this reusable sphincterotome may provide a means to decrease costs associated with endoscopic retrograde cholangiopancreatography.

Reuse of disposable sphincterotomes for diagnostic and therapeutic ERCP: a one-year prospective study.

BACKGROUND: Although previous studies have documented that single-channel sphincterotomes can be sterilized and used up to 10 times, no studies have prospectively evaluated the reuse of disposable sphincterotomes. METHODS: Five- and six-French double-channel sphincterotomes marketed as one-time-use only were manually cleaned, sterilized with ethylene oxide, and used up to 10 times. Over a 1-year period, total number of uses as a cannulation or cutting device, reason for sphincterotome dysfunction, possible infectious complications were evaluated, and cost-savings associated with reuse were evaluated. RESULTS: The mean number of times sphincterotomes could be used in our institution was 3.4; a broken or stiff cutting wire was the main reason for discard. There were two infectious complications during the study period. Both were experienced by patients with unrelieved obstruction treated with new sphincterotomes. Contingent on the method used, total savings related to sphincterotome reuse was approximately $66,000. CONCLUSIONS: Double-channel sphincterotomes marketed as one-time-use items can be reused safely when properly cleaned. Reuse was associated with significant cost savings in our institution.

Extracorporeal shock-wave lithotripsy for bile duct calculi.

BACKGROUND: Bile duct calculi (BDC) can be cleared or treated with modern endoscopic techniques in most patients. However, large stones, bile duct strictures, or unusual anatomy may make endoscopic clearance difficult. The purpose of the present study was to determine the efficacy of extracorporeal shock-wave lithotripsy (ESWL) in treating patients with complicated BDC. METHODS: Between 1989 and January 1995, 16 patients with BDC were treated at our institution with ESWL using a Dornier HM-3 lithotropter. The average age of patients was 62 years (range 32 to 88). Endoscopic retrograde cholangiopancreatography (ERCP) with sphincterotomy and attempted stone extraction (100%), nasobiliary drainage (83%), and biliary stents (6%) were used prior to ESWL. Eleven patients (61 %) had solitary stones, ranging in diameter from 0.5 to 2.6 cm, whereas 7 patients had multiple stones, ranging in diameter from 0.5 to 5.0 cm. The indications for ESWL were stone impaction (56%), stone size (38%), and bile duct stricture (6%). RESULTS: The 16 patients received 27 ESWL treatments (mean = 2101 shock at 21 kV); with 4 patients (22%) requiring multiple treatments. Stone fragmentation was achieved in 94% of patients. All patients had ERCP performed post-ESWL, and only 2 (13%) patients required immediate operations. At discharge, 94% of patients were stone-free. Minor complications (eg, pain, hematuria) were common. With an average follow-up of 3 years, only 1 patient (6%) has required retreatment for BDC. Hepatic transplantation was required in an additional patient. CONCLUSIONS: In this cohort of patients with both major medical comorbidities and/or technical contraindications to standard methods of endoscopic and surgical clearance of BDC, we found that ESWL facilitated stone clearance in 94% of patients with minimal morbidity and no mortality. In our opinion, ESWL should be used more frequently in the treatment of these complex patients.

Transpapillary stenting for pancreaticocutaneous fistulas.

Because transpapillary stents have been successfully placed to treat the ductal disruptions associated with pseudocysts, pancreatic ascites and pleural effusions, and pancreaticoenteric fistulas, we reviewed our experience with endoscopically placed prostheses in patients who had persistent pancreaticocutaneous fistulas but an otherwise intact duct. Nine patients who underwent endoscopic transpapillary stent placement for ongoing pancreaticocutaneous fistulas at our institution were retrospectively reviewed. Fistulas were present for a mean (+/-SEM) of 35 +/- 11 days and averaged 225 +/- 55 ml of output daily. Etiology of the fistulas included percutaneous pseudocyst drainage in four patients, pancreatic necrosis in two, complications of pancreatic surgery in two, and perforation of the duct of Santorini at the time of minor sphincterotomy in one. All patients had an otherwise intact duct at the time of endoscopic retrograde cholangiopancreatography. Six patients had transpapillary stents placed that did not bridge the area of leakage and three had prostheses placed across the ductal disruption. Eight of nine fistulas were successfully closed by means of this technique including five within 48 hours. There was one instance of stent migration and one patient developed prosthesis occlusion and an infected pseudocyst, which was treated with stent exchange. Stents were retrieved 10 to 14 days after fistula closure and no patient has had a recurrence at a median follow-up of 3 years. Transpapillary stents appear to effect closure of pancreaticocutaneous fistulas that fail to respond to conventional therapy.

Expandable versus conventional esophageal prostheses: easier insertion may not preclude subsequent stent-related problems.

BACKGROUND: Although expandable esophageal endoprostheses may be easier to insert and are associated with fewer procedure-related perforations, data comparing clinical results with these stents to those obtained with conventional prostheses are sparse. METHODS: We reviewed the records of all patients undergoing esophageal stent placement at our institution between October 1983 and July 1995 to define relative risks, clinical results, and need for reintervention prior to death, contrasting conventional to a variety of expandable esophageal endoprostheses. RESULTS: Over the period of review, 47 patients had conventional prostheses (CP) and 38 had expandable prostheses (EP) placed. Fifteen of 44 patients with CP and 14 of 38 with EP for malignancy also had esophago-airway fistulas. Insertion complications, prestent and poststent dysphagia scores, and complete fistula occlusion rates were comparable. Subacute complications were higher in the patients receiving EP (80%) than in those receiving CP (60%), possibly related to the prospective accumulation of data in patients receiving EP. Survival data were virtually identical and approximated 3 months for either group. CONCLUSIONS: Although both CP and EP improve dysphagia and occlude tracheoesophageal fistulae, patients ill enough to require a prosthesis do poorly regardless of prosthesis design. Moreover, although EP may be easier to insert than CP, stent- and patient-related problems persist and may require additional intervention.

Endoscopic approach to pancreas divisum.

Pancreas divisum has been claimed to be a harmless congenital variant or to occasionally cause acute relapsing pancreatitis (ARP), chronic pancreatitis (CP), or a chronic abdominal pain (CAP) syndrome. Both surgical and endoscopic approaches to accessory papilla decompression have been promulgated and widely disparate results reported in the literature. We retrospectively reviewed a five-year experience with dorsal pancreatic duct decompression at our institution utilizing a variety of endotherapeutic techniques. Data collected included procedural complications; patient interpretation of pre- and posttherapy pain, frequency, and intensity graded on an analog pain scale; frequency of hospitalization; and patient perception of "global" improvement to endotherapy. At a mean follow-up of 20 months, there was a statistically significant decrease in pancreatitis incidence in 15 patients with ARP (P = 0.016) and 19 patients with CP (P = 0.025). The frequency and intensity of chronic pain was also significantly improved (P < 0.001) in the latter group. In contrast, only one of five patients with CAP and normal dorsal pancreatography and secretin tests experienced global improvement, and there was no improvement utilizing an analog pain scale (P = 0.262) in the group as a whole. There was a 20% incidence of mild procedure or subsequent stent-related pancreatitis and an 11.5% accessory papilla restenosis rate. It is concluded that a subset of carefully selected patients with pancreas divisum may respond to endotherapy but that long-term follow-up will be required to define its ultimate place in the management of symptomatic patients with this anomaly.

Esophageal dilation can be done safely using selective fluoroscopy and single dilating sessions.

Maxims for safe esophageal dilation have included recommendations to use fluoroscopy in all instances and to limit dilation sessions to 2-mm increments. We reviewed a 34-month experience of all esophageal dilations undertaken at a large multispecialty clinic to define adherence to these recommendations and to delineate whether deviation was associated with significant complications. Four hundred thirty-two patients underwent 716 courses of esophageal dilation during this time, 92% of whom had benign disease. Eighty-nine percent of patients were dilated with polyvinyl dilators (Savary/American) and only 8% of these patients required fluoroscopic monitoring for the bougienage. Seventy-eight percent of the dilating sessions for patients without achalasia were undertaken using either a single large dilator (> or = 45 Fr) or employed incremental dilator sizes > 2 mm (6 Fr) in a single session. There was a single perforation in 662 nonachalasia dilations and this was a consequence of attempted placement of an esophageal endoprosthesis. We conclude that use of guide wire technology and newer dilating techniques do away with the need for routine fluoroscopic control. Moreover, single large dilators or dilator increments > 2 mm may be safely used, contingent on endoscopic stricture assessment.

Endoscopic pancreatic duct sphincterotomy: indications, technique, and analysis of results.

Fifty-six patients, 54 of whom had chronic pancreatitis, underwent endoscopic pancreatic duct sphincterotomy during a 4-year period from 1988 to 1992. Acute complications noted in 10% of patients included exacerbation of pancreatitis (4) and cholangitis (2). Chronic complications included induction of asymptomatic ductal changes in 16%, thought to be related to endoprosthesis placement, and stenosis of the sphincterotomy site in 14%, requiring repeated endoscopic or surgical sphincter section. When combined with a number of ancillary procedures, including removal of obstructing ductal calculi and stent placement for ductal disruption or stenosis, pancreatic duct sphincterotomy was associated with amelioration of chronic pain or decreased number of clinical attacks of pancreatitis in a subset of patients. The authors conclude that endoscopic pancreatic duct sphincterotomy enlarges our endotherapeutic armamentarium and deserves additional evaluation.

Long-term outcome after endoscopic sphincterotomy in patients with biliary colic and suspected sphincter of Oddi dysfunction.

Seventy-three highly selected patients (35 type II, 38 type III) with intractable biliary-type pain were studied with biliary manometry after a baseline endoscopic retrograde cholangiopancreatography was normal or showed only duct dilatation. No differences between the two groups were noted in regard to baseline sphincter hypertension (60% versus 55%), improvement after endoscopic sphincterotomy at mean follow-up of 3 years, or post-procedure pancreatitis rates (15% versus 16%). Although not statistically significant, a tendency for patients with bile ducts > or = 12 mm to have sustained clinical improvement after sphincterotomy was noted in comparison with patients having ducts < 12 mm; an inverse correlation between improvement in symptoms and presence of an intact gallbladder at baseline was also seen. The authors suggest that the current classification, which divides patients with recurrent right upper quadrant pain into types I, II, and III, is inadequate to define either incidence of sphincter of Oddi dysfunction or subsequent response to endoscopic sphincterotomy.

Endoscopic treatment of biliary injury in the era of laparoscopic cholecystectomy.

During a 2-year period in which the application of laparoscopic cholecystectomy became widespread in the Pacific Northwest, 33 patients with surgically related bile duct injury were seen by the gastroenterology section of a large multi-specialty clinic. Twenty-nine of these patients had anatomy amenable to endoscopic approach, and 25 of the 29 are symptom-free, with normal ultrasonography and serum liver function tests, at a minimum of 1 year of follow-up after undergoing a variety of endotherapeutic procedures. The authors conclude that endoscopic therapy, in conjunction with percutaneous drainage of large bilomas, is effective treatment for cystic duct leak and minor damage to the common bile duct. Further data and prolonged follow-up are required in patients with more significant biliary injury who undergo endoscopic endoprosthesis and/or dilation therapy.

Prospective evaluation of costs of disposable accessories in diagnostic and therapeutic ERCP.

Procedural (room fee) reimbursement from insurance payers is usually fixed for individual endoscopic procedures and may not include the costs of disposable equipment. This study estimated costs of disposable items used in ERCP procedures and calculated the percentage of total reimbursement spent on such equipment. A total of 248 ERCPs were performed in a 5-month study period, 192 (77%) of which were therapeutic. Total reimbursement was estimated to be $112,262 ($452 per procedure) and total disposable equipment costs were $47,195 ($190 per procedure), or 42% of total reimbursement. Disposable instrument costs in diagnostic ERCP approximated 13% of those associated with therapeutic ERCP, and the latter costs in turn utilized more than 60% of Medicare/Medicaid room fee reimbursement. This reimbursement may be inadequate to cover both disposable instrument costs and other procedural expenses, such as admit-recovery costs, nursing assistance, expenses related to endoscope purchase and capitalization, and equipment cleaning or sterilization. Our data suggest the need for either re-usable endoscopic accessories or adequate compensation to cover disposable instrument costs.

Endoscopic retrograde cholangiopancreatography after laparoscopic cholecystectomy.

We assessed the use of endoscopic retrograde cholangiopancreatography (ERCP) after laparoscopic cholecystectomy (LC) at our hepatobiliary referral center. This assessment included patients from outside institutions with post-LC problems. Between May 1990 and September 1992, we performed 522 LCs and 1,723 ERCP examinations. There were 78 patients who underwent 143 ERCP examinations after LC, 65% of whom were referred. ERCP findings were categorized as follows: normal results (8%), problems inherent to stone disease (65%), and iatrogenic injury (27%). The types of inherent problems were common bile duct (CBD) stones, pancreatitis, and papillary stenosis/microlithiasis. Within the CBD stone group, 5 of 26 patients also had papillary stenosis, and, within the pancreatitis group, 9 of 11 patients also had papillary stenosis, making papillary stenosis the most frequent observation (55%). Almost all of these patients (96%) required endoscopic papillotomy for successful treatment. The iatrogenic injury group was comprised of 21 patients, 16% of whom had cystic duct leak and 84% of whom had CBD injury. These patients required a variety of endoscopic procedures including endoscopic papillotomy (67%), CBD endoscopic stenting (76%), percutaneous drainage of biloma (29%), and percutaneous transhepatic biliary drainage (24%). Open surgical procedures after endoscopic assessment or treatment were required in only three patients in the iatrogenic group and in none in the inherent group. At this time, long-term follow-up is not possible with regard to biliary stricture. We conclude that the majority of problems after LC are either due to papillary stenosis/microlithiasis with or without CBD stones or to biliary injury. Both can be successfully diagnosed and treated with endoscopic techniques.

Endoscopic approach to pancreatic duct calculi and obstructive pancreatitis.

Twelve patients with chronic pancreatitis and obstructing pancreatic calculi underwent endoscopic retrograde cholangiopancreatography and attempted pancreatic stone extraction. This procedure, utilizing conventional stone baskets and balloons, as well as extracorporeal or laser lithotripsy in a subset, was ultimately successful in 11 of 12 patients. Nine of the 10 patients with relapsing pancreatitis have not had a symptomatic flare at a mean follow-up of 17 months. In contrast, neither of the patients who presented with chronic pain had convincing symptomatic improvement. The authors conclude that endoscopic removal of pancreatic duct calculi deserves further investigation in the treatment of relapsing attacks of chronic pancreatitis.

Pancreaticoenteric fistula: no longer a surgical disease?

We report our experience with eight patients with severe persistent pancreatitis associated with peripancreatic fluid collections requiring placement of drainage catheters who subsequently developed pancreatic fistula. The fistulas were diagnosed by endoscopic retrograde cholangiopancreatography, contrast tube study, or Hypaque enema at a mean of 13 weeks after diagnosis of pancreatitis and drain placement. These fistulas involved the duodenum in five patients and colon in three patients. Six patients had fistula resolution with medical therapy (after removal of percutaneous drainage catheters in three and with drain removal in conjunction with transpapillary stenting of a disrupted pancreatic duct in another three). We conclude that in patients with ongoing pancreatitis, pancreaticoenteric fistulas are probably caused by erosion of percutaneous drainage catheters. Such fistulas resolved with conservative treatment in six of eight patients.

Metallic self-expanding stent application in the upper gastrointestinal tract: caveats and concerns.

Ten patients with a variety of upper gastrointestinal tract stenoses precluding conventional prostheses or associated with recurrent occlusions of these prostheses, had an expandable metal Z stent placed. All patients had successful insertion (esophagus, five; biliary, three; afferent loop, one; efferent loop, one), although there was a tendency for the prostheses to delivery distally (gut) or proximally (biliary tree). Despite patency rates for up to 6 months in the esophagus and 1 year in the biliary tree, additional data and design modifications are required before widespread utilization.

Portal colopathy: prospective study of colonoscopy in patients with portal hypertension.

Twenty patients with portal hypertension related to a variety of causes prospectively underwent colonoscopy for hematochezia (n = 10), hemoccult positive stool and anemia (n = 9), or polyp found with screening flexible sigmoidoscopy (n = 2) (includes 1 patient with anemia/heme-positive stool). Twelve patients (60%) had previously undergone a course of sclerotherapy, and 10 (50%) had endoscopic evidence of congestive gastropathy. Colonoscopic findings included mucosal abnormalities resembling multiple vascular ectasias in 14 (70%), 4 of whom also had endoscopic features suggesting a mild, chronic colitis. Neither signs of chronic liver disease nor stigmata suggestive of more severe portal hypertension correlated with the colonoscopic findings. Two patients required heater probe therapy for actively oozing lesions resembling vascular ectasias and an additional two patients sclerotherapy for bleeding midrectal varices. Although likely an overestimate of the frequency, this study suggests that portal colopathy can occur in portal hypertension. Vascular ectasialike lesions in such settings may be associated with acute as well as chronic gastrointestinal bleeding and may require pharmacological, directed endoscopic, or portal decompressive therapy. Additional studies are required to determine not only the pathophysiology but also the true frequency of this entity.