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Out with the old and in with the new: a comparison of rectal suction biopsies with traditional and modern biopsy forceps
Journal of Pediatric Surgery (2009) 44, 395–398
www.elsevier.com/locate/jpedsurg
Out with the old and in with the new: a comparison of rectal suction biopsies with traditional and modern biopsy forceps Nigel J. Hall ⁎, D. Kufeji, A. Keshtgar Department of Paediatric Surgery, University Hospital Lewisham, London, UK Received 2 October 2008; accepted 23 October 2008
Key words: Hirschsprung disease; Rectal suction biopsy; Infant; Neonate
Abstract Aims: Rectal suction biopsy, the gold standard for the diagnosis of Hirschsprung disease, has been associated with a varying incidence of complications and inadequate biopsy. The rbi2 is a modern alternative to the ‘Noblett’ biopsy forceps and has recently become available. The aim of this study was to compare the performance of this novel tool with the Noblett forceps. Methods: Single-center retrospective study of all infants (b1 year) undergoing rectal suction biopsy from January 2004 to December 2007. During the study period, 2 different biopsy forceps were used— the Noblett forceps (first 2.5 years) and the rbi2 (last 1.5 years). A specimen was defined as inadequate if it was too small or contained inadequate submucosa for histological diagnosis. Fisher's Exact test and Mann-Whitney U test were used as appropriate. Results: During the study period, 238 specimens were obtained from 88 infants in 102 biopsy episodes. Overall, 13 episodes were inadequate. There were no demographic differences between the 2 groups, and no serious complications (hemorrhage requiring transfusion, rectal perforation, pelvic sepsis) occurred in any infant. A significantly higher proportion of specimens taken with the Noblett forceps were inadequate compared with the rbi2 (Noblett 30/153 [20%] vs rbi2 6/85 [7%]; Relative risk (RR) = 2.8; 95% confidence interval, 1.2-6.3; P = .01). There was a nonsignificantly higher incidence of inadequate biopsy episode with the Noblett forceps compared with the rbi2 (Noblett 10/63 [16%] vs rbi2 3/40 [7%]; RR = 2.2; 95% confidence interval, 0.6-7.3; P = .24). The rbi2 carries a small cost premium for each biopsy episode compared with the Noblett forceps, but this is low when compared with the cost of repeat biopsy. Conclusions: Rectal suction biopsy is a safe procedure with a low incidence of complications. The rbi2 offers superior efficacy over the Noblett forceps, and its use is likely to be more cost-effective. © 2009 Elsevier Inc. All rights reserved.
Presented at the 55th Annual Congress of the British Association of Paediatric Surgeons, Salamanca, Spain, July 2-5, 2008. ⁎ Corresponding author. Department of Paediatric Surgery Southampton University Hospital, SO16 6YD Southampton, UK. Tel.: +44 07976 153315; fax: +44 023 8079 7450. E-mail address: [email protected] (N.J. Hall). 0022-3468/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2008.10.093
Histopathological examination of rectal biopsy is the gold standard for the diagnosis of Hirschsprung disease (HD). The rectal suction biopsy (RSB), as described and popularized by Noblett [1,2], is a well-established technique providing tissue for diagnosis without the need for general anesthesia. However, the biopsy specimen may not include sufficient submucosa for histological examination resulting in the need to repeat the biopsy.
396 Recently, the rbi2 (Aus Systems, Allenby Gardens, South Australia), a novel RSB forceps has become commercially available. The proposed advantages of this ‘new’ forceps over the ‘old’ Noblett-style forceps include consistency of specimen as it uses a single-use disposable sharp blade [3], which may reduce the need for repeat biopsy. This study was undertaken to compare the adequacy of RSB specimens when performed using the Noblett biopsy forceps and this novel device.
1. Methods A retrospective review was performed of all infants (b1 year of age) undergoing RSB during a 4-year period from January 2004 to December 2007. Only infants undergoing RSB were included; open rectal biopsies or ‘punch’ rectal biopsies were excluded. During the study period, 2 different biopsy forceps were used. The ‘Noblett’ biopsy forceps was used for the first 2 1/2 years. After this, our unit used the rbi2 biopsy forceps for the most recent 1 1/2 years. Biopsies were taken 2 to 4 cm above the dentate line, and a 20-mL syringe was used to provide suction with both instruments. In our unit, the blade on the Noblett forceps was sharpened whenever it was felt necessary, and a spare sharp blade for the Noblett biopsy forceps was always available for use. The rbi2 biopsy forceps uses a new blade for each biopsy. The case notes and histopathology department database were reviewed to obtain demographic details, grade of operator performing the biopsy, and the report for each biopsy episode. A biopsy episode was defined as an episode of biopsy resulting in a set of biopsy specimens sent to the laboratory for analysis. A specimen was defined as inadequate if it was too small or contained inadequate submucosa for histological diagnosis. A biopsy episode was considered inadequate if all specimens taken within the episode were inadequate and a repeat biopsy was recommended. An attempt was made to determine costs for each biopsy episode using each instrument by determining the cost of equipment purchase and sterilization, biopsy processing, and admission. These were obtained from the hospital information department. Data are median (range) unless otherwise stated. Fisher's Exact test and Mann-Whitney U test were used as appropriate for statistical analysis.
N.J. Hall et al. specimens were obtained from 102 biopsy episodes. The median number of specimens per biopsy episode was 2 (range, 1-4). Overall, 13 episodes were inadequate resulting in either repeat RSB (included in this analysis) or open rectal biopsy (not included). No infant had a serious complication (hemorrhage requiring transfusion, rectal perforation, or pelvic sepsis). Final diagnosis was aganglionosis in 32 (36%) cases, ganglion cells were identified in 55 (including 2 infants with immature ganglion cells), and 1 case was assumed to be normal, based on equivocal histological findings and low clinical suspicion of HD (biopsy not repeated).
2.2. Comparison of old and new There were no significant demographic differences between infants undergoing RSB with the Noblett biopsy forceps and the rbi2 (Table 1). A significantly higher proportion of specimens taken with the Noblett forceps were inadequate compared with the rbi2 (Noblett 30/153 [20%] vs rbi2 6/85 [7%]; RR = 2.8; 95% confidence interval, 1.2-6.3; P = .01). There was a nonsignificantly higher incidence of inadequate biopsy episode with the Noblett forceps compared with the rbi2 (Noblett 10/62 [16%] vs rbi2 3/40 [7%]; RR = 2.2; 95% confidence interval, 0.6-7.3; P = .24). These data are shown in Fig. 1 The median number of specimens taken per biopsy episode was 2 for both forceps (range, 1-4 for Noblett forceps and 1-3 for rbi2). The proportion of biopsies performed by a trainee (ie, non-consultant) was similar between the 2 groups (Noblett 51/62 [82%] vs rbi2 35/40 [88%]; P = .58). The remaining biopsies were performed by consultants. The current purchase price of the Noblett biopsy forceps is £750 and for the rbi2 £299. During the study period, neither instrument was replaced. The cost per biopsy episode for cleaning and sterilization, histological processing, and analysis was the same for both instruments and was £28.76. Each biopsy episode performed with the rbi2 carries an additional cost related to the pack of disposable biopsy capsules, which currently to our unit is £44.50. Sharpening the Noblett biopsy knife carried a negligible cost, which was part of the cleaning and sterilization process. Inadequate
Table 1 Demographic details of infants undergoing RSB with either ‘old’ or ‘new’ biopsy forceps Old
2. Results 2.1. Patients and outcome During the study period, 88 infants less than 1 year of age underwent RSB for investigation of suspected HD. Median age at biopsy was 20 days (range, 2-320), and weight at biopsy was 3.25 kg (1.46-8.81). A total of 238
Biopsy episodes 62 Males, n (%) 37 (60) Gestational age at birth (wk) 38 (25-41) Birth weight (kg) 3.3 (0.8-4.2) Age at biopsy (d) 20 (2-320) Weight at biopsy (kg) 3.3 (1.5-6.0)
New
Pa
40 26 (65) 39 (26-41) 3.1 (1.1-4.9) 14 (2-210) 3.2 (1.7-8.8)
.68 .73 .44 .76 .33
Data are median (range) unless otherwise indicated. a Mann-Whitney U test.
Comparison of RSB with traditional and modern biopsy forceps
Fig. 1 Adequate and inadequate biopsy specimens and episodes with ‘old’ and ‘new’ instruments.
RSB inevitably results in additional hospital stay. In our unit, the cost of a 24-hour stay on the pediatric surgical ward is £250, and on the special care baby unit £286. It was not possible to determine accurately the additional costs relating to repeat biopsy for each instrument because of additional days in hospital because some children were dealt with as day cases and others underwent RSB as part of an inpatient episode. A comparison of this important issue was therefore not undertaken.
3. Discussion Inadequate RSB specimens result in diagnostic delay, considerable parental anxiety, longer hospital stay, and higher cost of treatment. Although the RSB without general anesthesia is invaluable in the diagnosis of HD, there is a recognized failure rate, and the reported incidence of inadequate RSB is as high as 26% [4]. A successful biopsy requires the appropriate technique of maintaining adequate suction and using a sharp, clean-cutting blade. The specimen should be deep enough to include the submucosa and hence be representative for the diagnosis of Hirschsprung disease. In Noblett's original report, it was commented that careful maintenance of the instrument was necessary to ensure smooth operation and successful biopsy [2]. Manufacturers of the rbi2 biopsy forceps claim a consistent specimen is obtained as a result of precise suction and the use of a new sharp single use blade for each specimen [3]. Our results show that there is a 3-fold lower incidence of inadequate specimens with the new device compared with the old one. Importantly, this benefit was not at the expense of an increased risk of complications. Although the incidence of inadequate biopsy episode was also lower
397
with the new instrument, this did not reach statistical significance. This discrepancy can be explained by the fact that multiple specimens were taken within each biopsy episode. With an increased number of patients, the number of inadequate biopsy episodes might also reach statistical significance. An additional proposed advantage of the rbi2 forceps is that the potential for patient-to-patient cross infection is eliminated because the portion of the device that comes into contact with the patient is single-use and disposable [3]. Although the incidence of patient-to-patient cross infection has not been investigated after the use of reusable RSB forceps, there is evidence to support the potential for such infection from surgical instruments in general [5,6]. Our cost comparison reveals that the rbi2 does carry a slight cost premium per biopsy episode related to the disposable biopsy capsules, which contain the single-use disposable blade. Although the cost of performing an RSB with the new device is greater than with the old device, this additional cost is low compared to the likely costs involved in repeating a biopsy, the most significant of which are related to extended hospital stay or an extra admission episode. Another potential weakness of our study is that we were unable to control for the individual performing the procedure. Biopsies were performed by too many individual trainee or consultant surgeons to adjust our results for the individual performing the procedure. However, we were able to record the grade (ie, consultant or trainee) of operator performing the biopsy and found that the grade of surgeon performing the biopsy was similar between the 2 groups. Although there may therefore be inter-operator variability in the performance of each RSB device, it does not appear that the devices perform differently in the hands of trainees or consultants. The success of any device used for RSB must include its ability to achieve consistent adequate biopsies regardless of operator. A potential contributing factor is that it is possible that the blade of the Noblett forceps was not as sharp as the blade of the rbi2. This is almost inevitable given that the rbi2 blade is single use. In our unit, the blade on the Noblett forceps was sharpened whenever it was felt necessary, and a spare sharp blade for the Noblett biopsy forceps was always available for use. Therefore, the lack of a sharp blade is unlikely to account for the results we have observed. Although this study has disadvantages associated with a retrospective investigation, it appears that RSB is a safe and valuable procedure for diagnosis of HD. The rbi2 offers superior performance in taking adequate RSB and is likely to be cost-effective compared with the ‘old’ Noblett forceps. A prospective study comparing the relative performance of each instrument is therefore desirable. However, based on these data, the rbi2 appears to have advantages over the Noblett biopsy forceps when used in neonates and infants who require suction biopsy to investigate possible Hirschsprung disease.
398
References [1] Campbell PE, Noblett HR. Experience with rectal suction biopsy in the diagnosis of Hirschsprung's disease. J Pediatr Surg 1969;4:410-5. [2] Noblett HR. A rectal suction biopsy tube for use in the diagnosis of Hirschsprung's disease. J Pediatr Surg 1969;4:406-9. [3] http://www.aussystems.com.au, accessed on 28-5-2008.
N.J. Hall et al. [4] Kobayashi H, Li Z, Yamataka A, et al. Rectal biopsy: what is the optimal procedure? Pediatr Surg Int 2002;18:753-6. [5] Hogg NJ, Morrison AD. Resterilization of instruments used in a hospital-based oral and maxillofacial surgery clinic. J Can Dent Assoc 2005;71:179-82. [6] Murdoch H, Taylor D, Dickinson J, et al. Surface decontamination of surgical instruments: an ongoing dilemma. J Hosp Infect 2006;63: 432-8.
www.elsevier.com/locate/jpedsurg
Out with the old and in with the new: a comparison of rectal suction biopsies with traditional and modern biopsy forceps Nigel J. Hall ⁎, D. Kufeji, A. Keshtgar Department of Paediatric Surgery, University Hospital Lewisham, London, UK Received 2 October 2008; accepted 23 October 2008
Key words: Hirschsprung disease; Rectal suction biopsy; Infant; Neonate
Abstract Aims: Rectal suction biopsy, the gold standard for the diagnosis of Hirschsprung disease, has been associated with a varying incidence of complications and inadequate biopsy. The rbi2 is a modern alternative to the ‘Noblett’ biopsy forceps and has recently become available. The aim of this study was to compare the performance of this novel tool with the Noblett forceps. Methods: Single-center retrospective study of all infants (b1 year) undergoing rectal suction biopsy from January 2004 to December 2007. During the study period, 2 different biopsy forceps were used— the Noblett forceps (first 2.5 years) and the rbi2 (last 1.5 years). A specimen was defined as inadequate if it was too small or contained inadequate submucosa for histological diagnosis. Fisher's Exact test and Mann-Whitney U test were used as appropriate. Results: During the study period, 238 specimens were obtained from 88 infants in 102 biopsy episodes. Overall, 13 episodes were inadequate. There were no demographic differences between the 2 groups, and no serious complications (hemorrhage requiring transfusion, rectal perforation, pelvic sepsis) occurred in any infant. A significantly higher proportion of specimens taken with the Noblett forceps were inadequate compared with the rbi2 (Noblett 30/153 [20%] vs rbi2 6/85 [7%]; Relative risk (RR) = 2.8; 95% confidence interval, 1.2-6.3; P = .01). There was a nonsignificantly higher incidence of inadequate biopsy episode with the Noblett forceps compared with the rbi2 (Noblett 10/63 [16%] vs rbi2 3/40 [7%]; RR = 2.2; 95% confidence interval, 0.6-7.3; P = .24). The rbi2 carries a small cost premium for each biopsy episode compared with the Noblett forceps, but this is low when compared with the cost of repeat biopsy. Conclusions: Rectal suction biopsy is a safe procedure with a low incidence of complications. The rbi2 offers superior efficacy over the Noblett forceps, and its use is likely to be more cost-effective. © 2009 Elsevier Inc. All rights reserved.
Presented at the 55th Annual Congress of the British Association of Paediatric Surgeons, Salamanca, Spain, July 2-5, 2008. ⁎ Corresponding author. Department of Paediatric Surgery Southampton University Hospital, SO16 6YD Southampton, UK. Tel.: +44 07976 153315; fax: +44 023 8079 7450. E-mail address: [email protected] (N.J. Hall). 0022-3468/$ – see front matter © 2009 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2008.10.093
Histopathological examination of rectal biopsy is the gold standard for the diagnosis of Hirschsprung disease (HD). The rectal suction biopsy (RSB), as described and popularized by Noblett [1,2], is a well-established technique providing tissue for diagnosis without the need for general anesthesia. However, the biopsy specimen may not include sufficient submucosa for histological examination resulting in the need to repeat the biopsy.
396 Recently, the rbi2 (Aus Systems, Allenby Gardens, South Australia), a novel RSB forceps has become commercially available. The proposed advantages of this ‘new’ forceps over the ‘old’ Noblett-style forceps include consistency of specimen as it uses a single-use disposable sharp blade [3], which may reduce the need for repeat biopsy. This study was undertaken to compare the adequacy of RSB specimens when performed using the Noblett biopsy forceps and this novel device.
1. Methods A retrospective review was performed of all infants (b1 year of age) undergoing RSB during a 4-year period from January 2004 to December 2007. Only infants undergoing RSB were included; open rectal biopsies or ‘punch’ rectal biopsies were excluded. During the study period, 2 different biopsy forceps were used. The ‘Noblett’ biopsy forceps was used for the first 2 1/2 years. After this, our unit used the rbi2 biopsy forceps for the most recent 1 1/2 years. Biopsies were taken 2 to 4 cm above the dentate line, and a 20-mL syringe was used to provide suction with both instruments. In our unit, the blade on the Noblett forceps was sharpened whenever it was felt necessary, and a spare sharp blade for the Noblett biopsy forceps was always available for use. The rbi2 biopsy forceps uses a new blade for each biopsy. The case notes and histopathology department database were reviewed to obtain demographic details, grade of operator performing the biopsy, and the report for each biopsy episode. A biopsy episode was defined as an episode of biopsy resulting in a set of biopsy specimens sent to the laboratory for analysis. A specimen was defined as inadequate if it was too small or contained inadequate submucosa for histological diagnosis. A biopsy episode was considered inadequate if all specimens taken within the episode were inadequate and a repeat biopsy was recommended. An attempt was made to determine costs for each biopsy episode using each instrument by determining the cost of equipment purchase and sterilization, biopsy processing, and admission. These were obtained from the hospital information department. Data are median (range) unless otherwise stated. Fisher's Exact test and Mann-Whitney U test were used as appropriate for statistical analysis.
N.J. Hall et al. specimens were obtained from 102 biopsy episodes. The median number of specimens per biopsy episode was 2 (range, 1-4). Overall, 13 episodes were inadequate resulting in either repeat RSB (included in this analysis) or open rectal biopsy (not included). No infant had a serious complication (hemorrhage requiring transfusion, rectal perforation, or pelvic sepsis). Final diagnosis was aganglionosis in 32 (36%) cases, ganglion cells were identified in 55 (including 2 infants with immature ganglion cells), and 1 case was assumed to be normal, based on equivocal histological findings and low clinical suspicion of HD (biopsy not repeated).
2.2. Comparison of old and new There were no significant demographic differences between infants undergoing RSB with the Noblett biopsy forceps and the rbi2 (Table 1). A significantly higher proportion of specimens taken with the Noblett forceps were inadequate compared with the rbi2 (Noblett 30/153 [20%] vs rbi2 6/85 [7%]; RR = 2.8; 95% confidence interval, 1.2-6.3; P = .01). There was a nonsignificantly higher incidence of inadequate biopsy episode with the Noblett forceps compared with the rbi2 (Noblett 10/62 [16%] vs rbi2 3/40 [7%]; RR = 2.2; 95% confidence interval, 0.6-7.3; P = .24). These data are shown in Fig. 1 The median number of specimens taken per biopsy episode was 2 for both forceps (range, 1-4 for Noblett forceps and 1-3 for rbi2). The proportion of biopsies performed by a trainee (ie, non-consultant) was similar between the 2 groups (Noblett 51/62 [82%] vs rbi2 35/40 [88%]; P = .58). The remaining biopsies were performed by consultants. The current purchase price of the Noblett biopsy forceps is £750 and for the rbi2 £299. During the study period, neither instrument was replaced. The cost per biopsy episode for cleaning and sterilization, histological processing, and analysis was the same for both instruments and was £28.76. Each biopsy episode performed with the rbi2 carries an additional cost related to the pack of disposable biopsy capsules, which currently to our unit is £44.50. Sharpening the Noblett biopsy knife carried a negligible cost, which was part of the cleaning and sterilization process. Inadequate
Table 1 Demographic details of infants undergoing RSB with either ‘old’ or ‘new’ biopsy forceps Old
2. Results 2.1. Patients and outcome During the study period, 88 infants less than 1 year of age underwent RSB for investigation of suspected HD. Median age at biopsy was 20 days (range, 2-320), and weight at biopsy was 3.25 kg (1.46-8.81). A total of 238
Biopsy episodes 62 Males, n (%) 37 (60) Gestational age at birth (wk) 38 (25-41) Birth weight (kg) 3.3 (0.8-4.2) Age at biopsy (d) 20 (2-320) Weight at biopsy (kg) 3.3 (1.5-6.0)
New
Pa
40 26 (65) 39 (26-41) 3.1 (1.1-4.9) 14 (2-210) 3.2 (1.7-8.8)
.68 .73 .44 .76 .33
Data are median (range) unless otherwise indicated. a Mann-Whitney U test.
Comparison of RSB with traditional and modern biopsy forceps
Fig. 1 Adequate and inadequate biopsy specimens and episodes with ‘old’ and ‘new’ instruments.
RSB inevitably results in additional hospital stay. In our unit, the cost of a 24-hour stay on the pediatric surgical ward is £250, and on the special care baby unit £286. It was not possible to determine accurately the additional costs relating to repeat biopsy for each instrument because of additional days in hospital because some children were dealt with as day cases and others underwent RSB as part of an inpatient episode. A comparison of this important issue was therefore not undertaken.
3. Discussion Inadequate RSB specimens result in diagnostic delay, considerable parental anxiety, longer hospital stay, and higher cost of treatment. Although the RSB without general anesthesia is invaluable in the diagnosis of HD, there is a recognized failure rate, and the reported incidence of inadequate RSB is as high as 26% [4]. A successful biopsy requires the appropriate technique of maintaining adequate suction and using a sharp, clean-cutting blade. The specimen should be deep enough to include the submucosa and hence be representative for the diagnosis of Hirschsprung disease. In Noblett's original report, it was commented that careful maintenance of the instrument was necessary to ensure smooth operation and successful biopsy [2]. Manufacturers of the rbi2 biopsy forceps claim a consistent specimen is obtained as a result of precise suction and the use of a new sharp single use blade for each specimen [3]. Our results show that there is a 3-fold lower incidence of inadequate specimens with the new device compared with the old one. Importantly, this benefit was not at the expense of an increased risk of complications. Although the incidence of inadequate biopsy episode was also lower
397
with the new instrument, this did not reach statistical significance. This discrepancy can be explained by the fact that multiple specimens were taken within each biopsy episode. With an increased number of patients, the number of inadequate biopsy episodes might also reach statistical significance. An additional proposed advantage of the rbi2 forceps is that the potential for patient-to-patient cross infection is eliminated because the portion of the device that comes into contact with the patient is single-use and disposable [3]. Although the incidence of patient-to-patient cross infection has not been investigated after the use of reusable RSB forceps, there is evidence to support the potential for such infection from surgical instruments in general [5,6]. Our cost comparison reveals that the rbi2 does carry a slight cost premium per biopsy episode related to the disposable biopsy capsules, which contain the single-use disposable blade. Although the cost of performing an RSB with the new device is greater than with the old device, this additional cost is low compared to the likely costs involved in repeating a biopsy, the most significant of which are related to extended hospital stay or an extra admission episode. Another potential weakness of our study is that we were unable to control for the individual performing the procedure. Biopsies were performed by too many individual trainee or consultant surgeons to adjust our results for the individual performing the procedure. However, we were able to record the grade (ie, consultant or trainee) of operator performing the biopsy and found that the grade of surgeon performing the biopsy was similar between the 2 groups. Although there may therefore be inter-operator variability in the performance of each RSB device, it does not appear that the devices perform differently in the hands of trainees or consultants. The success of any device used for RSB must include its ability to achieve consistent adequate biopsies regardless of operator. A potential contributing factor is that it is possible that the blade of the Noblett forceps was not as sharp as the blade of the rbi2. This is almost inevitable given that the rbi2 blade is single use. In our unit, the blade on the Noblett forceps was sharpened whenever it was felt necessary, and a spare sharp blade for the Noblett biopsy forceps was always available for use. Therefore, the lack of a sharp blade is unlikely to account for the results we have observed. Although this study has disadvantages associated with a retrospective investigation, it appears that RSB is a safe and valuable procedure for diagnosis of HD. The rbi2 offers superior performance in taking adequate RSB and is likely to be cost-effective compared with the ‘old’ Noblett forceps. A prospective study comparing the relative performance of each instrument is therefore desirable. However, based on these data, the rbi2 appears to have advantages over the Noblett biopsy forceps when used in neonates and infants who require suction biopsy to investigate possible Hirschsprung disease.
398
References [1] Campbell PE, Noblett HR. Experience with rectal suction biopsy in the diagnosis of Hirschsprung's disease. J Pediatr Surg 1969;4:410-5. [2] Noblett HR. A rectal suction biopsy tube for use in the diagnosis of Hirschsprung's disease. J Pediatr Surg 1969;4:406-9. [3] http://www.aussystems.com.au, accessed on 28-5-2008.
N.J. Hall et al. [4] Kobayashi H, Li Z, Yamataka A, et al. Rectal biopsy: what is the optimal procedure? Pediatr Surg Int 2002;18:753-6. [5] Hogg NJ, Morrison AD. Resterilization of instruments used in a hospital-based oral and maxillofacial surgery clinic. J Can Dent Assoc 2005;71:179-82. [6] Murdoch H, Taylor D, Dickinson J, et al. Surface decontamination of surgical instruments: an ongoing dilemma. J Hosp Infect 2006;63: 432-8.