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Magnetic resonance imaging–guided laparoscopic-assisted anorectoplasty for imperforate anus
Journal of Pediatric Surgery (2010) 45, 220–223
www.elsevier.com/locate/jpedsurg
Magnetic resonance imaging–guided laparoscopic-assisted anorectoplasty for imperforate anus George R. Raschbaum ⁎, John C. Bleacher, J. Damien Grattan-Smith, Richard A. Jones Children's Healthcare of Atlanta at Scottish Rite, Atlanta, GA 30342-4725, USA Received 5 October 2009; accepted 6 October 2009
Key words: Imperforate anus; MRI; Anorectoplasty; Laparoscopy
Abstract Purpose: Magnetic resonance imaging (MRI) has been well described as a modality for evaluation of a failed anorectal pull-through procedure for imperforate anus. To the authors' knowledge, intraoperative MRI has not been previously used to guide a laparoscopic-assisted anorectoplasty (LAARP). We propose that such a procedure would assure anatomically correct placement of the pulled-through rectum. Methods: Three male patients with imperforate anus and a prostatic urethral fistula underwent an MRI-guided LAARP in an operative MRI suite. The patients' ages ranged from 5 to 6 months at the time of their pullthrough procedure. Preoperative MRIs with mineral oil within the distal colostomy were performed on all patients to document the anatomy of the rectourethral fistula and its relationship to the parasagittal and vertical muscle complex. The perineum was pierced with an MRI compatible needle at the central portion of the parasagittal muscle complex as determined by a direct muscle stimulator. Further incremental advancement of the needle within the muscle complex was guided by serial MRIs in axial, coronal, and sagittal planes until the levator floor was penetrated, and the peritoneal cavity was entered. LAARP was then completed. Results: Completion MRI demonstrated placement of the pulled-through segment in a central location through the length of the muscle complex. Serial MRIs performed intraoperatively during advancement of the localization needle demonstrated a curved path of the vertical fibers. Attempts to nonincrementally advance the needle in a straight plane resulted in a breach of the vertical muscle complex or eccentric placement of the needle. Conclusions: Magnetic resonance imaging–guided LAARP results in anatomically correct placement of the rectum within the vertical muscle complex. Straight needle advancement techniques in LAARP could result in a deviation of the pulled-through rectum from the central muscular path. Further follow-up will be required to demonstrate functional advantage. © 2010 Elsevier Inc. All rights reserved.
The posterior sagittal approach for correction of imperforate anus revolutionized not only the surgical management but also the anatomical and physiologic concepts of anorectal Presented at the 40th Annual Meeting of the American Pediatric Surgical Association, Fajardo, Puerto Rico, May 28-June 1, 2009. ⁎ Corresponding author. Tel.: +1 404 252 3353; fax: +1 404 252 0645. E-mail address: [email protected] (G.R. Raschbaum). 0022-3468/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2009.10.033
malformations [1,2]. When the principles of minimally invasive surgery were applied to the posterior sagittal anorectoplasty for high imperforate anus, the laparoscopicassisted anorectoplasty (LAARP) evolved [3]. A limitation of the LAARP is that the narrow path of the vertical muscle fibers between the pelvic floor and perineal parasagittal muscle fibers cannot be visualized. This raises the potential for veering off course of the central portion of the vertical
MRI–guided LAARP for imperforate anus muscle complex while performing a pull through of the rectal segment to the perineum. To minimize the potential of poor placement of the pulled-through rectal segment, we have shown the use of an intraperitoneal laparoscopic peritoneal stimulator at LAARP to increase the accuracy of placement of the pulled-through rectal segment [4]. Also, intraoperative ultrasound and endorectal ultrasound have been demonstrated to improve accurate placement of the rectal segment [5,6]. The usefulness of magnetic resonance imaging (MRI) in the evaluation of anorectal malformations is well established [7-9]. Excellent visualization of the urethra, urinary fistula, rectum, and vertical-parasagittal muscle complex as well as associated anomalies is possible. Magnetic resonance imaging has also been commonly used to define the anatomy of a pulled-through rectal segment with poor postoperative results [10]. The advent of intraoperative MRI suites has led to accurate localization of both intracranial and extracranial tumors at the time of surgical procedures [11,12]. The authors review their experience with use of intraoperative MRI for guiding the pulled-through segment in LAARP.
1. Materials and methods The charts and surgical notes of 3 male patients with imperforate anus and a rectoprostatic urethral fistula, which had undergone an MRI-guided LAARP since June of 2008, were reviewed (IRB#08-106). All patients had undergone a divided colostomy within the first 2 days of life. Outpatient noncontrast MRIs were performed for surgical planning with a transurethral catheter in place, distal stoma mineral oil, and a vitamin E marker on the perineum at the central point of contraction of the parasagittal muscle fiber as evoked by a direct muscle stimulator (Pena Muscle Stimulator; Radionics Corporation, Burlington, Mass). Magnetic resonance imaging–guided LAARP was performed at 5 to 6 months of age in an intraoperative MRI suite (IMRIS, Manitoba, Canada) with a 1.5-T scanner. Patients were positioned in lithotomy within the MRI coil (Fig. 1). A baseline noncontrast MRI scan, in the manner previously described, was performed intraoperatively. A 20-gauge, 10-cm MRI compatible needle (#IBCHN-20-10-0; Cook Medical, Bloomington, Ind) was used to penetrate the perineal skin at the central site of the parasagittal muscle contraction as determined by direct muscle stimulation. Serial scans were obtained in axial, coronal, and sagittal planes as the needle was advanced cephalad to remain within the central portion of the vertical muscle complex until the peritoneal floor was penetrated. The MRI magnet was returned to its garage and LAARP was then performed in the manner described by Georgeson et al [3] with exception that the localization needle was identified in the peritoneum immediately after fistula division. A monofilament suture was then threaded through the localization needle, grasped
221
Fig. 1
The patient is in lithotomy position within the MRI coil.
endoscopically, and brought out through the umbilical site. This suture was used as a guide for advancement of serially larger dilators (WOGS-1200, Cook Medical) until a radially expanding 12-mm port (VS 1011012; AutoSuture, Norfolk, CT) could be accommodated. A completion MRI scan was obtained before leaving the intraoperative MRI suite. Stoma closure was performed at approximately 6 weeks after LAARP.
2. Results Excellent visualization of the rectum, prostatic fistula, and parasagittal-vertical muscle complex was noted on the baseline MRI performed in the MRI suite with the patient in the lithotomy position (Fig. 2). In all patients, a slight posterior curve of the path of the vertical fibers was noted in the sagittal plane. This curve required periodic adjustment of the localizing needle as it was advanced. A central path through the vertical muscles complex with the localizing needle was achieved in all patients. Completion MRI documented a good central position of the pulled-through rectum within the muscle complexes in the axial, coronal, and parasagittal planes (Fig. 3). The total procedure time averaged 450 minutes. This time was inclusive of a full preoperative and postoperative MRI, as well as repositioning and prepping of the patient for the various portions of the procedure. An average of 6 limited MRIs per patient was used for advancement of the localization needle through the muscle complex. In one patient, displacement of the needle during laparoscopy required repositioning the needle with a repeat MRI. In another patient, inadequate length of the colon distal to the colostomy required revision of the colostomy before the segment could be pulled through. Despite long anesthetic
222
G.R. Raschbaum et al. After colostomy closure, all patients stooled by the third postoperative day. No postoperative strictures or constipation has been noted in our patients to date.
3. Discussion
Fig. 2 A baseline MRI scan clearly demonstrates the urethra, urethral fistula, rectum, and vertical-parasagittal muscle complex in the sagittal plane. The nonlinear path of the central portion of the vertical muscle complex is noted.
times, there were no anesthetic complications, and patients were able to return to the regular patient care area. There were no postoperative infections or other surgical complications.
Magnetic resonance imaging has an established role in anatomical evaluation of patients with failed anorectal pull through procedures. It seemed intuitive to the authors that the use of MRI guidance to direct a LAARP could be used preemptively to avoid veering from the central portion of the muscle complexes. Only since the establishment of intraoperative MRI suites has this become a logistic reality. Our intraoperative MRI scans consistently demonstrated a posterior curve of the vertical muscle complex that required redirection of the needle as it was advanced to maintain a central position. There is a theoretical concern that advancing a localization needle in a straight path, as is frequently done currently, might breech the confines of the vertical muscle complex or result in an eccentric position within the complex. The MRI-guided LAARP also has the advantage of minimizing the dissection of the pelvic floor. In the authors' experience, identification of the muscles in the pelvic floor requires a more extensive dissection. In the MRIguided LAARP, the localization needle is readily apparent after division of the prostatic urethral fistula. As with many new techniques, much of the logistics involved a learning curve that contributed to longer operative times. Our plan is to shorten future operative times by using focused, limited, coned down MRI scans for needle advancement. Immediate postprocedure full MRI scans will no longer be performed. Although there is a theoretical advantage of the described technique, long-term follow-up will be required to validate any functional advantage of the MRI-guided LAARP. Increased operative times must be balanced against functional outcomes.
References
Fig. 3 The sagittal view of the completion MRI demonstrates a central location of the pulled-through rectum in the muscle complex.
[1] deVries PA, Pena A. Posterior sagittal anorectoplasty. J Pediatr Surg 1982;17:638-43. [2] Pena A. Advances in the management of anorectal malformations. New York (NY): Springer-Verlag; 1990. [3] Georgeson KE, Inge TH, Albanese CT. Laparoscopic assisted anorectal pull-through for high imperforate anus-a new technique. J Pediatr Surg 2000;35:927-31. [4] Iwanka T, Arai M, Kawashima H, et al. Findings of pelvic musculature and efficacy of laparoscopic-assisted anorectal pull-through for high imperforate anus. Surg Endosc 2003;17:278-81. [5] Yamataka A, Yoshida R, Kobayashi H, et al. Intraoperative endosonography enhances laparoscopic-assisted colon pull-through for high imperforate anus. J Pediatr Surg 2003;37:1657-60. [6] Kubota A, Kawahara H, Okuyama H, et al. Laparoscopic assisted anorectoplasty using perineal ultasonographic guide a preliminary report. J Pediatr Surg 2005;40:1535-8.
MRI–guided LAARP for imperforate anus [7] Aslam A, Grier DJ, Duncan AW, et al. The role of magnetic resonance imaging in the preoperative assessment of anorectal anomalies. Pediatr Surg Int 1998;14:71-3. [8] McHugh K. The role of radiology in children with anorectal anomalies: with particular emphasis on MRI. EJR 1998;26:194-9. [9] Golonka NR, Haga LJ, Keating RP, et al. Routine MRI evaluation of low imperforate anus reveals unexpected high incidence of tethered spinal cord. J Pediatr Surg 2002;37:966-9.
223 [10] Wong KKY, Khong PL, Lin SCL, et al. Post-operative magnetic resonance evaluation after laparoscopic anorectoplasty for imperforate anus. Int J Colorectal Dis 2004;20:33-7. [11] Hall WA, Truit CL. Intraoperative MR-guided neurosurgery. J Magn Reson Imaging 2008;27:368-75. [12] Lewin JS, Nour SG, Meyers ML, et al. Intraoperative MRI with a rotating surgical table: a time study and clinical results in 122 patients. Am J Roentgenol 2007;189:1096-103.
www.elsevier.com/locate/jpedsurg
Magnetic resonance imaging–guided laparoscopic-assisted anorectoplasty for imperforate anus George R. Raschbaum ⁎, John C. Bleacher, J. Damien Grattan-Smith, Richard A. Jones Children's Healthcare of Atlanta at Scottish Rite, Atlanta, GA 30342-4725, USA Received 5 October 2009; accepted 6 October 2009
Key words: Imperforate anus; MRI; Anorectoplasty; Laparoscopy
Abstract Purpose: Magnetic resonance imaging (MRI) has been well described as a modality for evaluation of a failed anorectal pull-through procedure for imperforate anus. To the authors' knowledge, intraoperative MRI has not been previously used to guide a laparoscopic-assisted anorectoplasty (LAARP). We propose that such a procedure would assure anatomically correct placement of the pulled-through rectum. Methods: Three male patients with imperforate anus and a prostatic urethral fistula underwent an MRI-guided LAARP in an operative MRI suite. The patients' ages ranged from 5 to 6 months at the time of their pullthrough procedure. Preoperative MRIs with mineral oil within the distal colostomy were performed on all patients to document the anatomy of the rectourethral fistula and its relationship to the parasagittal and vertical muscle complex. The perineum was pierced with an MRI compatible needle at the central portion of the parasagittal muscle complex as determined by a direct muscle stimulator. Further incremental advancement of the needle within the muscle complex was guided by serial MRIs in axial, coronal, and sagittal planes until the levator floor was penetrated, and the peritoneal cavity was entered. LAARP was then completed. Results: Completion MRI demonstrated placement of the pulled-through segment in a central location through the length of the muscle complex. Serial MRIs performed intraoperatively during advancement of the localization needle demonstrated a curved path of the vertical fibers. Attempts to nonincrementally advance the needle in a straight plane resulted in a breach of the vertical muscle complex or eccentric placement of the needle. Conclusions: Magnetic resonance imaging–guided LAARP results in anatomically correct placement of the rectum within the vertical muscle complex. Straight needle advancement techniques in LAARP could result in a deviation of the pulled-through rectum from the central muscular path. Further follow-up will be required to demonstrate functional advantage. © 2010 Elsevier Inc. All rights reserved.
The posterior sagittal approach for correction of imperforate anus revolutionized not only the surgical management but also the anatomical and physiologic concepts of anorectal Presented at the 40th Annual Meeting of the American Pediatric Surgical Association, Fajardo, Puerto Rico, May 28-June 1, 2009. ⁎ Corresponding author. Tel.: +1 404 252 3353; fax: +1 404 252 0645. E-mail address: [email protected] (G.R. Raschbaum). 0022-3468/$ – see front matter © 2010 Elsevier Inc. All rights reserved. doi:10.1016/j.jpedsurg.2009.10.033
malformations [1,2]. When the principles of minimally invasive surgery were applied to the posterior sagittal anorectoplasty for high imperforate anus, the laparoscopicassisted anorectoplasty (LAARP) evolved [3]. A limitation of the LAARP is that the narrow path of the vertical muscle fibers between the pelvic floor and perineal parasagittal muscle fibers cannot be visualized. This raises the potential for veering off course of the central portion of the vertical
MRI–guided LAARP for imperforate anus muscle complex while performing a pull through of the rectal segment to the perineum. To minimize the potential of poor placement of the pulled-through rectal segment, we have shown the use of an intraperitoneal laparoscopic peritoneal stimulator at LAARP to increase the accuracy of placement of the pulled-through rectal segment [4]. Also, intraoperative ultrasound and endorectal ultrasound have been demonstrated to improve accurate placement of the rectal segment [5,6]. The usefulness of magnetic resonance imaging (MRI) in the evaluation of anorectal malformations is well established [7-9]. Excellent visualization of the urethra, urinary fistula, rectum, and vertical-parasagittal muscle complex as well as associated anomalies is possible. Magnetic resonance imaging has also been commonly used to define the anatomy of a pulled-through rectal segment with poor postoperative results [10]. The advent of intraoperative MRI suites has led to accurate localization of both intracranial and extracranial tumors at the time of surgical procedures [11,12]. The authors review their experience with use of intraoperative MRI for guiding the pulled-through segment in LAARP.
1. Materials and methods The charts and surgical notes of 3 male patients with imperforate anus and a rectoprostatic urethral fistula, which had undergone an MRI-guided LAARP since June of 2008, were reviewed (IRB#08-106). All patients had undergone a divided colostomy within the first 2 days of life. Outpatient noncontrast MRIs were performed for surgical planning with a transurethral catheter in place, distal stoma mineral oil, and a vitamin E marker on the perineum at the central point of contraction of the parasagittal muscle fiber as evoked by a direct muscle stimulator (Pena Muscle Stimulator; Radionics Corporation, Burlington, Mass). Magnetic resonance imaging–guided LAARP was performed at 5 to 6 months of age in an intraoperative MRI suite (IMRIS, Manitoba, Canada) with a 1.5-T scanner. Patients were positioned in lithotomy within the MRI coil (Fig. 1). A baseline noncontrast MRI scan, in the manner previously described, was performed intraoperatively. A 20-gauge, 10-cm MRI compatible needle (#IBCHN-20-10-0; Cook Medical, Bloomington, Ind) was used to penetrate the perineal skin at the central site of the parasagittal muscle contraction as determined by direct muscle stimulation. Serial scans were obtained in axial, coronal, and sagittal planes as the needle was advanced cephalad to remain within the central portion of the vertical muscle complex until the peritoneal floor was penetrated. The MRI magnet was returned to its garage and LAARP was then performed in the manner described by Georgeson et al [3] with exception that the localization needle was identified in the peritoneum immediately after fistula division. A monofilament suture was then threaded through the localization needle, grasped
221
Fig. 1
The patient is in lithotomy position within the MRI coil.
endoscopically, and brought out through the umbilical site. This suture was used as a guide for advancement of serially larger dilators (WOGS-1200, Cook Medical) until a radially expanding 12-mm port (VS 1011012; AutoSuture, Norfolk, CT) could be accommodated. A completion MRI scan was obtained before leaving the intraoperative MRI suite. Stoma closure was performed at approximately 6 weeks after LAARP.
2. Results Excellent visualization of the rectum, prostatic fistula, and parasagittal-vertical muscle complex was noted on the baseline MRI performed in the MRI suite with the patient in the lithotomy position (Fig. 2). In all patients, a slight posterior curve of the path of the vertical fibers was noted in the sagittal plane. This curve required periodic adjustment of the localizing needle as it was advanced. A central path through the vertical muscles complex with the localizing needle was achieved in all patients. Completion MRI documented a good central position of the pulled-through rectum within the muscle complexes in the axial, coronal, and parasagittal planes (Fig. 3). The total procedure time averaged 450 minutes. This time was inclusive of a full preoperative and postoperative MRI, as well as repositioning and prepping of the patient for the various portions of the procedure. An average of 6 limited MRIs per patient was used for advancement of the localization needle through the muscle complex. In one patient, displacement of the needle during laparoscopy required repositioning the needle with a repeat MRI. In another patient, inadequate length of the colon distal to the colostomy required revision of the colostomy before the segment could be pulled through. Despite long anesthetic
222
G.R. Raschbaum et al. After colostomy closure, all patients stooled by the third postoperative day. No postoperative strictures or constipation has been noted in our patients to date.
3. Discussion
Fig. 2 A baseline MRI scan clearly demonstrates the urethra, urethral fistula, rectum, and vertical-parasagittal muscle complex in the sagittal plane. The nonlinear path of the central portion of the vertical muscle complex is noted.
times, there were no anesthetic complications, and patients were able to return to the regular patient care area. There were no postoperative infections or other surgical complications.
Magnetic resonance imaging has an established role in anatomical evaluation of patients with failed anorectal pull through procedures. It seemed intuitive to the authors that the use of MRI guidance to direct a LAARP could be used preemptively to avoid veering from the central portion of the muscle complexes. Only since the establishment of intraoperative MRI suites has this become a logistic reality. Our intraoperative MRI scans consistently demonstrated a posterior curve of the vertical muscle complex that required redirection of the needle as it was advanced to maintain a central position. There is a theoretical concern that advancing a localization needle in a straight path, as is frequently done currently, might breech the confines of the vertical muscle complex or result in an eccentric position within the complex. The MRI-guided LAARP also has the advantage of minimizing the dissection of the pelvic floor. In the authors' experience, identification of the muscles in the pelvic floor requires a more extensive dissection. In the MRIguided LAARP, the localization needle is readily apparent after division of the prostatic urethral fistula. As with many new techniques, much of the logistics involved a learning curve that contributed to longer operative times. Our plan is to shorten future operative times by using focused, limited, coned down MRI scans for needle advancement. Immediate postprocedure full MRI scans will no longer be performed. Although there is a theoretical advantage of the described technique, long-term follow-up will be required to validate any functional advantage of the MRI-guided LAARP. Increased operative times must be balanced against functional outcomes.
References
Fig. 3 The sagittal view of the completion MRI demonstrates a central location of the pulled-through rectum in the muscle complex.
[1] deVries PA, Pena A. Posterior sagittal anorectoplasty. J Pediatr Surg 1982;17:638-43. [2] Pena A. Advances in the management of anorectal malformations. New York (NY): Springer-Verlag; 1990. [3] Georgeson KE, Inge TH, Albanese CT. Laparoscopic assisted anorectal pull-through for high imperforate anus-a new technique. J Pediatr Surg 2000;35:927-31. [4] Iwanka T, Arai M, Kawashima H, et al. Findings of pelvic musculature and efficacy of laparoscopic-assisted anorectal pull-through for high imperforate anus. Surg Endosc 2003;17:278-81. [5] Yamataka A, Yoshida R, Kobayashi H, et al. Intraoperative endosonography enhances laparoscopic-assisted colon pull-through for high imperforate anus. J Pediatr Surg 2003;37:1657-60. [6] Kubota A, Kawahara H, Okuyama H, et al. Laparoscopic assisted anorectoplasty using perineal ultasonographic guide a preliminary report. J Pediatr Surg 2005;40:1535-8.
MRI–guided LAARP for imperforate anus [7] Aslam A, Grier DJ, Duncan AW, et al. The role of magnetic resonance imaging in the preoperative assessment of anorectal anomalies. Pediatr Surg Int 1998;14:71-3. [8] McHugh K. The role of radiology in children with anorectal anomalies: with particular emphasis on MRI. EJR 1998;26:194-9. [9] Golonka NR, Haga LJ, Keating RP, et al. Routine MRI evaluation of low imperforate anus reveals unexpected high incidence of tethered spinal cord. J Pediatr Surg 2002;37:966-9.
223 [10] Wong KKY, Khong PL, Lin SCL, et al. Post-operative magnetic resonance evaluation after laparoscopic anorectoplasty for imperforate anus. Int J Colorectal Dis 2004;20:33-7. [11] Hall WA, Truit CL. Intraoperative MR-guided neurosurgery. J Magn Reson Imaging 2008;27:368-75. [12] Lewin JS, Nour SG, Meyers ML, et al. Intraoperative MRI with a rotating surgical table: a time study and clinical results in 122 patients. Am J Roentgenol 2007;189:1096-103.