Stricture-free survival in 46 patients after repair of laparoscopic bile duct injury by means of the Hepp-Couinaud approach (data from Murr et al12).
Polar graph using median values for each of the 36-Item Short-Form Health Survey subscales for 45 patients undergoing surgical bile duct repair (cases) and 44 patients undergoing uneventful laparoscopic cholecystectomy (controls). PF indicates physical functioning; RP, role-physical; RE, role-emotional; BP, bodily pain; VT, vitality; MH, mental health; SF, social functioning; and GH, general health.
Polar graph using median values for each of the 36-Item Short-Form Health Survey subscales for 45 patients undergoing surgical bile duct repair (cases) and US norms. PF indicates physical functioning; RP, role-physical; RE, role-emotional; BP, bodily pain; VT, vitality; MH, mental health; SF, social functioning; and GH, general health.
Sarmiento JM, Farnell MB, Nagorney DM, Hodge DO, Harrington JR. Quality-of-Life Assessment of Surgical Reconstruction After Laparoscopic Cholecystectomy–Induced Bile Duct InjuriesWhat Happens at 5 Years and Beyond?. Arch Surg. 2004;139(5):483-489. doi:10.1001/archsurg.139.5.483
Quality of life of patients after biliary reconstruction for laparoscopic injuries is comparable to that of patients after laparoscopic cholecystectomy.
Tertiary referral center.
Records of 59 consecutive patients undergoing surgical reconstruction of the biliary tract after injury induced by laparoscopic cholecystectomy between 1990 and 1997 were reviewed. Hepp-Couinaud technique or Roux-en-Y hepaticojejunostomy was used in 53 patients; other procedures included cholangiojejunostomy, choledochorrhaphy, and hepaticoduodenostomy.
Quality-of-life questionnaires (36-Item Short-Form Health Survey [SF-36]) were mailed to each patient in the group and to patients who underwent uneventful laparoscopic cholecystectomy, matched individually by year, sex, and age group. Values from the general population matched by age and sex were gathered (national norms). Minimum time of follow-up was 5 years.
Eighty-nine (81%) of 110 potential respondents to the survey completed the SF-36 questionnaires. All 8 values evaluated in the SF-36 questionnaire (physical functioning, role-physical, bodily pain, general health perceptions, vitality, social functioning, role-emotional, and mental health index) for patients undergoing biliary reconstruction were similar to those of both their matched controls (all P >.10) and national norms (all P >.05). The standardized physical component scale was also similar between the 2 groups (cases vs controls, 51 vs 48; P = .47), as was the standardized mental component scale (cases vs controls, 55 vs 55; P = .60).
With a minimum of 5 years of follow-up, the quality of life after surgical biliary reconstruction compares favorably with that of both patients undergoing uneventful laparoscopic cholecystectomy and national norms.
Since it was introduced in the early 1990s, laparoscopic cholecystectomy has become the preferred approach in patients with symptomatic gallbladder disease. As the surgical community has gained wide experience with laparoscopic cholecystectomy and the technique has become integrated into the curriculum of graduate surgical education, the incidence of major bile duct injury has plateaued at 0.4% to 0.6%.1- 3 Given that more than 700 000 cholecystomies are performed annually,4 clearly hepatobiliary surgeons will continue not infrequently to perform biliary reconstruction for laparoscopic cholecystectomy–induced bile duct injury.
In expert hands, the results after repair of laparoscopic cholecystectomy–induced bile duct injury have been excellent or good in approximately 90% of patients, as assessed by grading systems that use standard clinical measures such as pain, results of liver function studies, cholangitis, jaundice, and need for reintervention.5- 11 Our experience has likewise been gratifying.12 In 59 consecutive patients who underwent biliary reconstruction from January 1, 1990, through December 31, 1997, after laparoscopic cholecystectomy–induced bile duct injury, we found excellent to good results in 49 of 54 patients (91%) when our patients were surveyed a mean of 3.7 years after operation (2 patients died and 3 were lost to follow-up).12 A number of these patients continue to return for annual or biennial follow-up, and we have been impressed that their subjective quality of life (QOL) has been excellent.
The report by Boerma et al13 addressing in an objective manner the QOL after bile duct injury during laparoscopic cholecystectomy and a subsequent editorial14 were noteworthy. Boerma et al concluded that, despite excellent functional outcome after repair, a bile duct injury has negative impact on QOL, even at long-term follow-up. Their well-done study piqued our interest in QOL assessment in such patients and prompted us to objectively evaluate the QOL at long-term follow-up in our previously described cohort of 59 consecutive patients undergoing biliary reconstruction after laparoscopic bile duct injury. Clinical outcome after biliary repair has been consistently excellent and undisputed. This study was focused and designed to test our hypothesis that the QOL after surgical biliary reconstruction for laparoscopic cholecystectomy–induced bile duct injury is excellent.
After approval by the Mayo Foundation Institutional Review Board, the records of 59 patients (8 men and 51 women [mean ± SD age, 45 ± 2 years]) who underwent surgical reconstruction of iatrogenic laparoscopic bile duct injuries at Mayo Clinic, Rochester, Minn, from January 1, 1990, through December 31, 1997, were reviewed. All patients had been externally referred at variable times (median, 5 months; range, 4 days to 6 years) after the injury. Forty-seven patients (80%) had had at least one or a combination of therapeutic percutaneous (n = 13), endoscopic (n = 20), or operative (n = 34) interventions before referral to our institution. According to the classification of Strasberg et al,15 more than 50% of the injuries involved the proximal biliary tree (E3, 25 [42%]; E4, 5 [8%]; E5, 3 [5%]). Class E1 injuries occurred in 5 patients (8%) and class E2 in 16 (27%). Isolated injuries to the right sectoral ducts were rare (class B, 2 patients; class C, 1 patient). Lateral injury (class D) occurred in only 2 patients.
The Hepp-Couinaud technique16 was used for repair in 46 of the 53 patients who underwent Roux-en-Y hepaticojejunostomy (Table 1). The Hepp-Couinaud technique was not used as part of the Roux-en-Y hepaticojejunostomy in 7 patients. The remaining 6 patients had Roux-en-Y cholangiojejunostomy (n = 3), choledochorrhaphy (n = 2), and hepaticoduodenostomy (n = 1). Transanastomotic stents were used in 43 patients a mean ± SD of 45 ± 3 days postoperatively. The mean ± SD length of stay was 9 ± 0.5 days.
One patient died postoperatively. Fifty-two patients (88%) had no complications. Ten complications developed in 7 patients. When the patients were surveyed in 1998, final outcome was graded in 54 patients (2 had died and 3 were lost to follow-up). Forty-six patients (85%) had excellent results, 3 patients (6%) had good results, and 5 patients (9%) subsequently developed anastomotic stricture that required intervention. These patients were considered to have treatment failure. The grading system for outcome was published in our group's previous report.12 Life-table analysis predicted 95% and 88% chances of stricture-free survival, respectively, at 2 and 5 years when the Hepp-Couinaud technique was used (Figure 1).
Surviving patients who had undergone biliary reconstruction were matched by age, sex, and year of operation with patients who had experienced an uneventful laparoscopic cholecystectomy at the Mayo Clinic. Both cases and controls were contacted in 2002 for QOL assessment. We chose to limit our QOL analysis to the same patient cohort previously described, as their clinical outcome was well assessed and documented, and doing so would allow a minimum of 5 years of follow-up. The rationale for the latter was an effort both to assess long-term QOL and to minimize the impact of pending litigation on results.
We chose the 36-Item Short-Form Health Survey (SF-36) health status questionnaire, one of the most widely accepted QOL instruments, developed by Rand Corp under contract to the Health Care Financing Administration for the Medical Outcomes Study.17,18 The SF-36 measures 8 domains of QOL: physical functioning, role-physical, role-emotional, bodily pain, vitality, mental health, social functioning, and general health. All scores are standardized so that the worst possible score is 0 and the best possible score is 100. Each domain is scored separately and is not additive. National norms with percentiles and standard deviations for each domain of the SF-36 have been published by the Medical Outcomes Trust.19
Cases and controls were contacted by our survey research center in 2002 and SF-36 questionnaires were mailed to both groups. The 1-page (front and back) survey is completed by the study participant with a No. 2 lead pencil, returned by mail, and scored electronically. If no response was received within 1 month, a reminder was mailed to each participant. After 2 months without completion, participants were contacted by telephone.
Median values from the healthy population, matched by age and sex (US norms), were accrued for comparison with the study cohort. Each domain's median value for the cases was compared with that of both laparoscopic cholecystectomy controls and US norms.
The impact on QOL was analyzed as a function of previous surgical repair, early or delayed reconstruction, duration of stenting, injury classification, use of the Hepp-Couinaud technique, and duration of follow-up.
The QOL scores were compared with US normal data by the Wilcoxon signed rank test. Scores were compared between cases and controls with the Wilcoxon rank sum test.
Of the 59 patients, 3 were known to have died during the follow-up period ending in 2002. Thus, 56 patients and 56 controls were studied for eligibility to survey. One patient had an institutional flag for pending legal issues and, along with the companion control, was excluded. Thus, 110 survey questionnaires were sent to 55 study patients and 55 laparoscopic cholecystectomy controls. Ten study patients and 11 controls were excluded from the survey or analysis because of death (1 subject), refusal (3 subjects), no response (7 subjects), lost to follow-up (3 subjects), and other (eg, incarcerated, foreign residence, physically unable to complete) (7 subjects). Thus, of the 110 surveys sent, 89 valid records (81%) (45 cases and 44 controls) were available for analysis.
The mean follow-up for the 45 patients who underwent surgical repair was 8.4 years (range, 5.2-11.4 years). There were 39 women and 6 men. Their mean ± SD age was 44 ± 16 years. The mean follow-up for the 44 control patients matched by age, sex, and year of surgery was 9.1 years (range, 6.0-11.8 years).
Table 2 describes the median values and ranges for each of the 8 subscales of the SF-36 for both the 45 patients undergoing surgical repair of their bile duct injury and the 44 control subjects who underwent uneventful laparoscopic cholecystectomy. In none of the 8 domains was the difference significantly different. The standardized physical component scale was also similar between the 2 groups (cases vs controls, 51 vs 48; P = .47), as was the standardized mental component scale (cases vs controls, 55 vs 55; P = .60). Likewise, comparison of the median values for each domain of the SF-36 for the 45 patients undergoing surgical repair of bile duct injury with national norms failed to show a difference for any of the 8 subscales.
With the use of the median values for both cases and controls, a series of polar graphs were constructed to visually display the data presented in Table 2. Figure 2 is a polar graph that uses the median values for the 45 patients undergoing surgical repair of bile duct injury (cases) and the 44 controls with uneventful laparoscopic cholecystectomy, resulting in images that are nearly superimposable. Figure 3 demonstrates graphically the median subscale scores for cases and US norms. Although the graphs are not superimposable, in none of the domains was there a statistically significant difference.
In an effort to determine whether any clinical factor impacted on QOL, the standardized physical and mental component scale scores for the 45 patients undergoing surgical repair were analyzed relative to influence of a previous attempt at repair, time interval from surgery to biliary reconstruction, duration of stenting, classification of injury (according to Strasberg et al15), use of Hepp-Couinaud technique, and duration of follow-up (Table 3). None of these clinical factors was found to significantly affect either the physical or mental component scale scores.
In our study, we found that the QOL as assessed by the SF-36 health survey a minimum of 5 years after biliary reconstruction for iatrogenic laparoscopic bile duct injury was comparable both to that of a control population of patients undergoing uneventful laparoscopic cholecystectomy and to US norms. Although we did not update the study cohort relative to objective assessment of clinical status, restricture, or reintervention, our previous report and those of others have documented the efficacy and durability of surgical repair of laparoscopic bile duct injury.5,7- 12 Moreover, in fewer than 5% of patients do symptoms or stricture develop beyond 5 years after surgical repair.20 The present study was focused and designed to assess QOL as determined by the study population by means of a recognized survey instrument rather than clinical outcome.
The literature is replete with studies confirming satisfactory technical and clinical outcome10,21- 25; however, few have addressed QOL in a robust manner. In a report by Boerma et al from the Netherlands,13 106 patients with laparoscopic bile duct injury treated endoscopically (n = 69), surgically (n = 32), or with interventional radiologic techniques (n = 5) were found to have excellent outcomes assessed clinically with a median follow-up of 70 months. Eighty-nine patients were available for ongoing study, of whom 82 (92%) responded to an SF-36 health survey. When compared with patients who underwent uneventful laparoscopic cholecystectomy and healthy, age- and sex-matched controls, study patients were found to have significantly poorer QOL in all 8 subscales. The QOL was no different for patients treated endoscopically or surgically.
Philosophical and methodologic differences between the report of Boerma et al and our study perhaps help explain the disparity in our respective conclusions regarding QOL after laparoscopic bile duct injury. First, the observation that of their 82 respondents, 36 had cystic duct or peripheral hepatic radical leaks and also were found to have poor QOL scores is incongruent with clinical experience. Second, the control group of patients who had laparoscopic cholecystectomy had undergone operation 2 years before assessment of QOL, much shorter than the interval for the study cohort. Also, it is not clear whether these controls were matched for age and sex. In our study, the control group was matched by age, sex, and year of operation. Third, in the Netherlands study, a large proportion of patients with major bile duct injury were treated endoscopically, often requiring periods of treatment spanning 6 months. We believe that major duct injuries should be managed surgically, which, although more invasive, is definitive and not punctuated by repetitive interventions. Finally, in the study of Boerma et al, the survey instrument used for the laparoscopic cholecystectomy control group (Medical Outcomes Study Short Form–24 [SF-24]) was different from that used to survey the study cohort (SF-36). In our study, both cases and controls completed identical SF-36 health surveys.
Melton et al26 assessed QOL of patients after surgical reconstruction of a major bile duct injury from laparoscopic cholecystectomy. Eighty-nine patients were sent surveys, of whom 54 (61%) responded. Similar surveys were sent to patients who underwent uneventful laparoscopic cholecystomy and healthy controls. Median follow-up was 59 months. The survey instrument, the City of Hope Medical Center QOL Survey, differed from the one used in our study; however, their conclusions were very similar to ours. The QOL scores for patients with surgically repaired bile duct injury were comparable to those of patients undergoing uncomplicated laparoscopic cholecystectomy and healthy controls in the physical and social domains, but were significantly lower in the psychological domain.
Possibly the lower scores in the psychological domain in the Melton et al study are explained by either "response shift bias" or the impact of prolonged stenting. Response shift bias is a phenomenon recognized in QOL assessment in patients with malignancy.27,28 Such patients tend to report a better QOL than anticipated on clinical grounds, perhaps because, in their hope to conquer the malignancy, their internal set point for QOL assessment is lowered. In contrast, as laparoscopic cholecystectomy is perceived as a minor procedure with no hospital stay and relatively short recovery, it is logical to imagine the disappointment of a patient facing a longer admission, longer recovery, unexpected time lost from gainful employment, and the possibility of a second operation.29
In our study, both mental and physical subscale scores were no different from those of controls. It can be speculated that our mean follow-up interval of 8.4 years minimized the effect of response shift bias.
With regard to stenting, only 9 of the 54 patients in the Melton et al study had stents for less than 4 months and 33 had them for longer than 9 months. The duration of stenting in our study was less. For the 43 of 59 patients who received stents, the mean duration was only 45 days.
Like Melton et al, we were unable to demonstrate an impact of various clinical factors on QOL. Previous repair, level of injury, duration of stenting, and length of follow-up were similarly found not to influence QOL. In addition, in our analysis, neither interval from injury to repair nor use of the Hepp-Couinaud technique was found to influence QOL.
Although they occur in only 1 in 200 patients undergoing laparoscopic cholecystectomy, repair and patient rehabilitation are costly. It has been estimated that each bile duct injury adds $50 000 to the cost of providing care.30 When surveyed in 1998, all but 2 of our 59 patients who had had bile duct injury after laparoscopic surgery expressed an interest in pursuing a claim of negligence.12 Ultimately, 33 (56%) of the 59 sought a legal remedy for their bile duct injury. In the Melton et al26 study, a lawsuit was associated with a poorer QOL assessment. Although we did not analyze the impact of legal action on QOL, our minimal follow-up period of 5 years was chosen to minimize the impact of litigation on results. To our knowledge, only 1 patient had an institutional flag for pending legal issues, and this patient was excluded.
Third-party payers and purchasers of health care have heightened interest in outcomes study and QOL. Velanovich31 critically reviewed surgical articles addressing QOL between 1996 and 1999 and concluded that a substantial number of studies made errors in conceptual design and in use of QOL instruments. He made suggestions and provided a framework that would be of assistance to surgeons interested in pursuing QOL research. To this end, for our study we chose a well-recognized QOL instrument, the SF-36. It is easy to answer (1 page, fill in blanks) and has been validated. It is a generic survey, which is appropriate for a condition lacking a disease-specific instrument (eg, gastroesophageal reflux disease). The study hypothesis was defined before the survey was sent, and statistical analysis was performed for each subscale between cases and controls. Furthermore, the SF-36 has been used for a variety of conditions of differing causes (debridement for acute pancreatitis,32 pancreas transplant,33 parathyroidectomy,34 lymphedema,35 laparoscopic antireflux surgery,36 bariatric surgery,37 proctocolectomy,38 and comparison of laparoscopic and open antireflux operations39) and has been determined to be reliable, responsive, and valid.31 Ideally, QOL would be assessed both before and after an intervention. The uncommon and unpredictable nature of bile duct injury at laparoscopic cholecystectomy renders this impractical.
In this study, we found that the QOL after surgical reconstruction of laparoscopic cholecystectomy–induced bile duct injuries was as good as that of a control population after uneventful laparoscopic cholecystectomy and US norms when assessed a minimum of 5 years after operation. We believe these observations further underpin our philosophy that the most durable solution to major bile duct injury is surgical repair. Our results are promising but represent a small subset of patients undergoing biliary reconstruction for bile duct injury and warrant validation by additional investigators in the field. In addition, QOL assessment for management of major bile duct injury with alternative therapies such as dilation and stenting is warranted.
Corresponding author: Michael B. Farnell, MD, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (e-mail: email@example.com).
Accepted for publication December 16, 2003.
This paper was presented at the 111th Scientific Session of the Western Surgical Association; November 11-13, 2003; Tucson, Ariz; and is published after peer review and revision. The discussions that follow this article are based on the originally submitted manuscript and not the revised manuscript.
A. Rahim Moossa, MD, San Diego, Calif: We have to face the fact that we surgeons are victims of our referral practice and also victims of the population that we serve. Since the results of these 2 papers appear to contradict each other, I quickly looked in our database attempting to find a consensus. After reading these 2 papers, I didn't have time to send my own questionnaires, but I found some relevant information.
Since 1989 we have seen 94 major bile duct injuries. By that I mean complete transection, excision, and/or devascularization of the main duct. Of these, 79 patients have been successfully repaired by all accepted criteria and have been followed serially for over 5 years. We have documented all of their complaints at each visit since we knew that this is what the lawyers ask us each time. Eighteen of our 79 patients were from overseas, and only 1 of them was involved in litigation—1 out of 18. Two of the 18 patients had very nonspecific digestive complaints that cannot be directly attributed to the bile duct injury. So my interpretation is that on the quality-of-life questionnaire, 2 out of 18 would have given a negative answer.
Of the 61 patients from the United States, 58 were involved in litigation. At 2 years after a successful repair, 53 of the 58 had multiple complaints. These included poor appetite and other digestive symptoms, alteration in bowel habits, weight gain, menstrual disturbances in women, depression, anxiety, nightmares, insomnia, tiredness, inability to concentrate at work, and painful abdominal scar. Following settlement of the litigation at 5 years, only 4 of the 53 patients had residual symptoms and 2 of the 4 had an unfavorable litigation outcome. So it does appear that the 2 factors for the patients' complaints are (1) evolution of time and (2) whether there is litigation going on or not.
My 3 questions to Dr Farnell are: (1) Have you serially documented the QOL measurements to see if they changed over time? (2) Have you found any correlation between QOL and outcome of litigation? (3) Have you found any difference in your QOL questionnaire between the American population and the overseas population?
Dr Farnell: Like Dr Pinson, my interest in this project was stimulated by the Amsterdam paper. It was my clinical perception that our patients who had bile duct reconstruction fared well. As I began to investigate the literature in this area, it became clear to me that clinical outcome as assessed by surgeons and QOL as assessed by the patient are 2 different things. This is the reason why when we did this project we did not update the clinical outcome of our patients. What really is important relative to QOL is the patient's own assessment of how they perceive their health and, to be objective, that recognized QOL instruments need to be used.
Why is our paper different from the conclusions that Dr Pinson brought to you this morning? I think the length of follow-up probably is the explanation. Our minimum follow-up period was 5 years. Clearly, litigation, as others have shown, does impact on qualify-of-life assessment. We tried to factor this issue out by excluding the only patient with pending litigation. The other is response shift bias. When patients have a problem like malignancy, they tend to respond optimistically with regard to their QOL because they are so glad to have another chance. On the other hand, patients who have a bile duct injury tend to be particularly negative; in other words, their set point for their QOL has shifted very far downward. With a minimum follow-up of 5 years, both the response shift bias issue and the effect of litigation have been minimized.
Dr Moossa asked about assessment of QOL over time. We have not had an opportunity to assess QOL over time in these patients. This is our initial effort in the realm of QOL assessment, and we have learned a lot doing this project and hope to do more in the future. We did not assess the impact of litigation, but I think you heard from Dr Pinson that it does have a negative impact on QOL and also in the other papers in the literature, both from Melton et al from Hopkins and from the Amsterdam group, it was clear that litigation did have a negative impact on outcome.
Dr Moossa asked about the overseas population. There were only about 4 patients in our group who were foreign and they were unable to respond to our questionnaire, so I did not have an opportunity to assess their QOL relative to our domestic patients.
Richard E. Burney, MD, Ann Arbor, Mich: It is terribly pleasing to see this organization begin to present data on QOL outcomes and also to begin to make the very important distinction between what we as surgeons consider our results, but which are sometimes called "outcomes," and real outcomes. Results are still our results; patient-reported outcomes are the true outcomes. Both are important, but it is very important to make that distinction, Dr Farnell, as you did. My concern in looking at these data and comparing them to the data from Vanderbilt that we just heard is that there may be a methodologic error here. When we started doing QOL data 10 years ago, we discovered that it could be a tricky business. Responses may vary depending on how you administer the questionnaires, what instructions the people are given, whether it is done over the phone or not, whether it is done in person or not; these can make a big difference. Some of the things that Dr Thirlby pointed out in terms of socioeconomic status and education can also make a big difference. I suspect there were some major differences between the socioeconomic status of the Mayo patients and that of the Vanderbilt patients. But when you see data that show 100 on several domain scores, it is usually a tip-off that there is something funny. That your patients appear to be supranormal in 3 domains tells me to be a little bit worried that there is a methodologic error somewhere. The data that were just presented from Vanderbilt are much more consistent with our own data on cholecystectomy patients and look more like what one would expect to see.
Dr Farnell: Dr Burney, thank you for your comments. You are right. When we compared our cases to US norms, it surprised me a little bit that our cases were supranormal relative to US norms. Our statisticians have observed this consistently when control populations cared for at Mayo score higher than national norms. Perhaps there are inherent differences between the population we serve in the upper Midwest and national norms. Relative to the supranormal scores of 100 in 3 domains of the SF-36, we utilized median rather than mean domain scores to perform our analysis. The mean domain scores that he referred to were in the 75 to 85 range. Medians were chosen for analysis due to the nongaussian distribution of our data set.
With regard to methodology, an SF-36 form was sent to the patients and controls. It's a form filled in with a No. 2 lead pencil and is mailed back. The only patients who were interviewed by phone where there might have been some bias brought into the equation were those few patients who did not respond after 2 reminders by mail.
Vic Velanovich, MD, Detroit, Mich: I just have a couple of questions here. You touched on this a little bit and I think it is worth emphasizing. You really are not measuring QOL or health-related QOL, but what we really are measuring here is patients' perceived QOL. That is a big difference between the actual health of the patient vs what they actually think about their health.
Toward that end, my question is, did you actually ask the patients what they thought was important after the injury or after the repair? What I have found is that when administering these questionnaires, what we think is important is not what the patient thinks is important, and we sometimes project what we think is important on these outcomes, so I think because it is such a patient-perceived outcome, we should be asking questions about what the patients think.
Lastly, the sample size may be zero here, but was there a difference between the patients who were referred in for their repair of their bile duct injury vs bile duct injuries that happened at the Mayo and you guys fixed yourself?
Dr Farnell: I will answer the last question first. All of these patients were referred. Fortunately, we did not have any patients who incurred bile duct injury at Mayo Clinic in this series of 59 patients.
In terms of what we asked the patients relative to what was important, we didn't ask the patients any questions. We did not supplement the SF-36 survey with any questions. We sent the patients the SF-36 health questionnaire with a short cover letter simply asking them to respond to the questionnaire. The reason we chose the SF-36 was because it had been used in the important paper from Amsterdam, and that's the report that stimulated our interest in QOL. In the paper from Hopkins, a different instrument was used—the City of Hope health questionnaire—but the findings in the paper from the Hopkins group were very similar to our own.