- Email: [email protected]
Minimally Invasive Resection of Intra-axial Posterior Fossa Tumors Using Tubular Retractors
Original Article
Minimally Invasive Resection of Intra-axial Posterior Fossa Tumors Using Tubular Retractors David Mampre, Alexandra Bechtle, Kaisorn L. Chaichana
OBJECTIVE: Posterior fossa tumor surgery is associated with a significant risk of complications, and the complications are typically more frequent compared with similar supratentorial surgeries. This study aimed to evaluate 1) the extent of resection and neurologic outcomes and 2) perioperative complications with use of minimally invasive approaches for intra-axial posterior fossa tumors from our case series.
-
METHODS: All consecutive patients who underwent nonbiopsy surgery of a posterior fossa tumor using tubular retractors and exoscopic visualization from January 2016 to May 2018 were prospectively identified and included.
-
RESULTS: During the reviewed period, 15 patients underwent resection of an intra-axial posterior fossa tumor. Eight (53%) patients were men, and the median age was 63.0 years (interquartile range: 45.0e67.5 years). The tumor was located in the cerebellar hemisphere in 11 (73%) cases, vermis in 3 (20%) cases, and middle cerebellar peduncle in 1 (7%) case. The median preoperative and postoperative lesion volumes were 21.6 cm3 (interquartile range: 10.1e33.0 cm3) and 0 cm3 (interquartile range: 0e1.2 cm3), respectively. The percent resection was 100% (92%-100%). Following surgery, 12 (80%) patients had improved and 3 (20%) patients had stable Karnofsky performance scale scores, whereas no patients had a decline in Karnofsky performance scale score postoperatively. No patients incurred other postoperative regional or medical complications.
-
posterior fossa intra-axial tumors with relatively high efficacy and low morbidity.
INTRODUCTION
P
osterior fossa surgery is associated with a significant risk of complications, and the complications are typically more frequent compared with similar supratentorial surgeries.1-3 In large institutional studies, this complication rate is approximately 25%e40%, and the major complications include cerebrospinal fluid (CSF) leaks and wound infections, among others.1-3 In addition, these surgeries are associated with significantly more pain likely because of the extensive muscle dissection, larger bony openings relative to lesion size, and entry into CSF spaces.4 Minimally invasive approaches may be associated with less morbidity and pain because the openings are smaller, involve less muscle dissection, potentially avoid CSF spaces, and have shorter durations.5-7 However, studies using minimally invasive approaches for posterior fossa intra-axial pathology are primarily limited to cadaveric studies.8,9 For the past couple of years, we have used minimally invasive approaches for posterior fossa tumors, and we hypothesize that this method is associated with high efficacy and low morbidity. The primary objectives of the present study were to evaluate extent of resection and neurologic outcomes, and the secondary objective was to evaluate perioperative complications with minimally invasive approaches for intra-axial posterior fossa tumors from our case series. MATERIALS AND METHODS
-
CONCLUSIONS: We demonstrated the possible efficacy of a minimally invasive approach with the use of tubular retractors and exoscopic visualization for resecting
Patient Selection This study received institutional review board approval (#72892). All consecutive patients who underwent nonbiopsy surgery
Key words Exoscope - Keyhole - Minimally invasive - Posterior fossa - Tubular retractor - Tumor
Department of Neurosurgery, Mayo Clinic, Jacksonville, Florida, USA
-
To whom correspondence should be addressed: Kaisorn L. Chaichana, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2018). https://doi.org/10.1016/j.wneu.2018.08.049 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com
Abbreviations and Acronyms CSF: Cerebrospinal fluid IQR: Interquartile range KPS: Karnofsky performance scale
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ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
performed by the senior author (K.L.C.) for a posterior fossa tumor using tubular retractors with exoscopic visualization from January 2016 to May 2018 were prospectively identified and included in this case series. The collected variables were age, sex, lesion location, preoperative and postoperative neurologic function and functional status (Karnofsky performance scale [KPS] score for tumor cases), preoperative and postoperative lesion volume, and follow-up duration. KPS scores were recorded immediately preoperatively, on discharge, and at subsequent follow-up visits. Preoperative and postoperative lesion volume were measured as previously described using semiautomated programming.10,11 For tumor cases, the tumor volumes were measured using T1-weighted magnetic resonance imaging with gadolinium for contrast-enhancing tumors and T2-weighted magnetic resonance imaging for nonecontrast-enhancing tumors. General Treatment Strategy Patients who presented with deep-seated, intra-axial posterior fossa lesions within the hemisphere, vermis, or cerebellar peduncles were considered for nonbiopsy surgical resection using tubular retractors. A tubular retractor was chosen to allow access to deep-seated lesions to minimize the need for conventional large
Figure 1. Example of a posterior fossa case with use of a tubular retractor. (A) A small 3-cm craniotomy is done. (B) Dura mater is opened in a cruciate fashion. (C) The cortex is cauterized in a linear fashion parallel to the folia.
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craniotomies, extensive white matter dissection, and use of retractor blades. Typically, these lesions were not superficially located (obviating the need for a tubular retractor), were not larger than 4.5 cm for tumor cases, were not primarily based in the brainstem, and were difficult to access using an extra-axial route. The goal of each case was to achieve maximal resection without causing significant or progressive neurologic deficit. Patients typically underwent preoperative imaging for intraoperative navigation purposes within 48 hours of surgery. In the operating room, the patient was placed prone on chest rolls with the pressure points padded. The patient was kept in a neutral position to help with intraoperative orientation. The trajectory toward the lesion was planned preoperatively and was chosen based on minimizing the potential morbidity associated with accessing the lesion. This was typically done through the cerebellar hemisphere (Figure 1). Resection was aimed at the contrast-enhancing portion of the lesion and not fluid attenuated inversion recovery changes for tumor cases. Per hospital protocol, patients were given 2 g cefazolin intravenously within 30 minutes of incision and 1 g every 8 hours for 24 hours postoperatively. For patients with penicillin allergies, 600 mg clindamycin was given intravenously within 30 minutes of incision, and 600 mg was given every 8 hours for 24 hours
(D) Ultrasound is used to guide the trajectory of the tubular retractor and to assess lesion resection. (E) The tumor is removed en bloc through the tubular retractor.
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2018.08.049
ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
postoperatively. Based on intraoperative navigation and surgical planning, a 3-cm linear skin incision was made overlying the planned trajectory. An approximately 2-cm craniotomy was made, and the dura mater was then opened in a cruciate fashion. A 0- or 90degree exoscope (Vitom; KARL STORZ-Endoscopy America, Inc., El Segundo, California, USA) attached to a pneumatic arm (UniARM; Mitaka USA, Inc., Park City, Utah, USA) was used to provide visualization and magnification through the tubular retractor, as previously described.5-7 The cerebellar hemisphere or vermis was cauterized parallel to the folia, and then the preselected tubular retractor (BrainPath; NICO Corporation, Indianapolis, Indiana, USA) was passed with the aid of frameless stereotactic guidance to reach the most superficial component for tumor cases. For smaller or deeper lesions, an ultrasound probe (Hitachi Aloka Medical America, Wallingford, Connecticut, USA) was used to establish appropriate trajectory and lesion localization. Once the lesion was accessed, the lesion was resected using suction, tissue-biting (Myriad; NICO Corporation), or bipolar cautery. Following resection, the retractor was withdrawn, and the dura, bone, and skin were closed in standard fashion. Postoperative magnetic resonance imaging was performed 1e2 days after surgery.
RESULTS The patients who were operated on using a tubular retractor and exoscopic visualization are summarized in Table 1 and Figure 2. During the reviewed period, 15 patients underwent resection of a posterior fossa tumor. Eight (53%) patients were men, and the median (interquartile range [IQR]) age of all patients was 63 years
(IQR: 45e67.5 years). The tumor was located in the cerebellar hemisphere in 11 (73%) cases, vermis in 3 (20%) cases, and middle cerebellar peduncle in 1 (7%) case. The median preoperative lesion volume was 21.6 cm3 (IQR: 10.1e33.0 cm3). The median preoperative KPS score was 70 (IQR: 60e70). The major presenting symptoms were headaches, nausea, and vomiting in 12 (85%) patients; ataxia and gait problems in 10 (60%) patients; and mental status changes in 5 (33%) patients. Following surgery, the median postoperative lesion volume was 0 cm3 (IQR: 0e1.2 cm3), and median percent resection was 100% (IQR: 92%e100%). Gross total resection was achieved in 12 (80%) cases. The remaining 3 cases were limited by involvement of the brainstem in 2 (13%) and tentorium in 1 (7%). There were no cases with hemostasis problems, and no cases with notable postoperative cavity hemorrhages. At 1 month postoperatively, median postoperative KPS score was 80 (IQR: 70e95). Following surgery, 12 (80%) patients had improved KPS scores, 3 (20%) patients had stable KPS scores, and no patients had a decline in KPS score. No patients experienced postoperative medical complications, including infection, CSF leak, pneumonia, deep vein thrombosis/ pulmonary embolism, sepsis, or seizures. There were no reports of worsened deficits, including motor weakness, language deficits, cranial nerve problems, and balance issues. The median follow-up duration was 6.4 months (IQR: 4.2e9.6 months) after surgery.
DISCUSSION In this case series of 15 patients who underwent minimally invasive resection of a posterior fossa intraparenchymal lesion, most
Table 1. Summary of Patients Who Underwent Resection of a Posterior Fossa Intra-axial Neoplasm Using Tubular Retractors with Exoscopic Visualization Patient
Age (Years)/Sex
Location
Pathology
Percent Resection
Preop KPS Score
Postop KPS Score
Improved KPS Score
1
78/F
Hemisphere
Metastatic
100%
30
90
Improved
2
49/F
MCP
Cavernoma
100%
60
100
Improved
3
23/F
Hemisphere
Hemangioblastoma
100%
80
100
Improved
4
69/F
Hemisphere
Metastatic
100%
60
70
Improved
5
63/M
Vermis
Metastatic
100%
70
80
Improved
6
51/M
Hemisphere
Metastatic
84%
70
70
Stable
7
32/F
Hemisphere
Metastatic
100%
90
100
Improved
8
37/M
Hemisphere
Cavernoma
100%
80
100
Improved
9
69/M
Vermis
Metastatic
100%
70
70
Stable
10
46/M
Vermis
Metastatic
90%
50
70
Improved
11
66/M
Hemisphere
Metastatic
92%
70
70
Stable
12
65/F
Hemisphere
Metastatic
100%
40
70
Improved
13
44/M
Hemisphere
Metastatic
100%
70
90
Improved
14
66/M
Hemisphere
Hemangioblastoma
100%
70
80
Improved
15
72/M
Hemisphere
Metastatic
89%
60
80
Improved
Preop, preoperative; KPS, Karnofsky performance scale; Postop, postoperative; F, female; MCP, middle cerebellar peduncle, M, male.
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ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
Figure 2. Cerebellar hemisphere hemangioblastoma. (AeC) A 19-year-old woman presented with nausea, vomiting, and ataxia and was found to have a cystic contrast-enhancing lesion in the right cerebellar hemisphere with significant vasogenic edema. (A) Axial T1-weighted magnetic resonance imaging with contrast enhancement. (B) Axial T2-weighted
patients did well after surgery. The median percent tumor resection was 100%; 85% of patients underwent gross total resection, whereas the remaining 15% had resection limited by brainstem or tentorial involvement. Of patients, 100% had improved and/or stable KPS score, whereas 85% improved, and no patients had a decline. At last follow-up, there were no incidences of infection, CSF leak, or other medical complications. Posterior fossa surgery can be associated with significant morbidity and mortality.1-3 Dubey et al.1 evaluated 500 patients operated on over a 10-year period at a single institution and found that 159 (31.8%) patients had complications. The complications included CSF leak in 65 (13%), meningitis in 46 (9.2%), and wound infection in 35 (7%) among patients who underwent resection of cerebellopontine angle tumors, microvascular decompression, cerebellar lesions, and Chiari malformations, among others. Brell et al.3 studied complications associated with intra-axial tumors in 200 patients with gliomas and metastases. Of patients 27.5% had complications, and
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imaging. (C) Sagittal T1-weighted imaging with contrast enhancement. (DeF) Patient underwent gross total resection with a tubular retractor and exoscopic visualization. (D) Axial T1-weighted imaging with contrast enhancement. (E) Axial T2-weighted imaging. (F) Coronal T1-weighted imaging with contrast enhancement.
infratentorial tumor location, previous radiation therapy, and reoperations were each independently associated with regional complications. Similarly, Cabantog and Bernstein12 reported a single surgeon’s experience with 207 consecutive patients, where the overall complication rate was 25.1%. They found that infratentorial location (44% vs. 25%) was associated with higher complications regardless of histology. A method of accessing deep-seated lesions is with the use of tubular retractors that provide a protected corridor with circumferential retraction.5-7,13-17 Early use of tubular retractors was for supratentorial lesions in the basal ganglia and thalamus.13,14 More recently, these approaches have been used for intracerebral hematomas, gliomas, and biopsies in deep-seated locations.5-7,15 The use of minimally invasive intracranial surgery may decrease the morbidity associated with posterior fossa intra-axial surgery. The principle of minimally invasive surgery is to be atraumatic, preserve the surrounding tissue, and still resect the lesion. This may allow for smaller incisions, less muscle dissection, smaller
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2018.08.049
ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
craniotomies, and less extensive white matter dissection.5-7 However, studies devoted to these techniques with posterior fossa pathology are limited to extra-axial pathology (i.e., microvascular decompression) and cadaveric studies.8,9,18 In the present study, there was no reported morbidity, and there was high efficacy with this approach. Among these patients, no patients worsened, whereas 12 (80%) and 3 (20%) had improved and stable KPS scores following surgery, respectively. Gross total resection was achieved in 12 (80%). All patients had deep-seated lesions and therefore represent challenging intra-axial posterior fossa pathology cases. This study is the first to our knowledge to describe the efficacy of using minimally invasive approaches for posterior fossa intra-axial surgery and provides an alternative to traditional open approaches. This approach may minimize the morbidity associated with infratentorial surgery, while maintaining extent of resection. In this study, we show that extensive resection can be maintained for tumors with low morbidity. Moreover, gross total resection was achieved in most patients, and cases without gross total resection were limited by eloquent or critical neurovascular involvement. This study has some limitations. The study was not designed to evaluate if this technique was better compared with conventional techniques in regard to surgical time, postoperative pain, complications, and extent of resection. The purpose of this study was to serve as a proof-of-principle to demonstrate that these
2. Hadanny A, Rozovski U, Nossek E, Shapira Y, Strauss I, Kanner AA, et al. Craniectomy versus craniotomy for posterior fossa metastases: complication profile. World Neurosurg. 2016;89: 193-198. 3. Brell M, Ibanez J, Caral L, Ferrer E. Factors influencing surgical complications of intra-axial brain tumours. Acta Neurochir (Wien). 2000;142: 739-750. 4. Beretta E, Vetrano IG, Curone M, Chiapparini L, Furlanetto M, Bussone G, et al. Chiari malformation-related headache: outcome after surgical treatment. Neurol Sci. 2017;38:95-98. 5. Gassie K, Wijeseekera O, Chaichana KL. Minimally invasive tubular retractor-assisted biopsy and resection of subcortical intra-axial gliomas and other neoplasms [e-pub ahead of print]. J Neurosurg Sci. https://doi.org/10.23736/S0390-5616. 18.04466-1. Accessed June 15, 2018. 6. Iyer R, Chaichana KL. Minimally invasive resection of deep-seated high-grade gliomas using tubular retractors and exoscopic visualization. J Neurol Surg A Cent Eur Neurosurg. 2018;79:330-336. 7. Jackson C, Gallia GL, Chaichana KL. Minimally invasive biopsies of deep-seated brain lesions using tubular retractors under exoscopic
CONCLUSIONS Surgery in the posterior fossa, regardless of pathology, is associated with a higher risk of morbidity and mortality. The standard approaches involve large incisions, extensive muscle dissection, and wide craniectomies and are associated with a multitude of complications. We describe the use of tubular retractors with exoscopic visualization as a minimally invasive approach to resect these intra-axial lesions with relatively high efficacy and low morbidity. This approach using tubular retractors in this case series was associated with extensive resection without associated morbidity.
visualization. J Neurol Surg A Cent Eur Neurosurg. 2017;78:588-594.
REFERENCES 1. Dubey A, Sung WS, Shaya M, Patwardhan R, Willis B, Smith D, et al. Complications of posterior cranial fossa surgery—an institutional experience of 500 patients. Surg Neurol. 2009;72: 369-375.
techniques can be used for intra-axial posterior fossa surgery. However, we acknowledge that our small sample size limits the ability to perform statistical analyses and prevents generalizability. Larger and/or randomized studies comparing this technique with standard techniques with longer follow-up are needed to evaluate survival outcomes. In addition, the short-term follow-up of the patients in this series prevents a detailed evaluation of possible long-term effects and/or neurologic deficits. Nevertheless, we believe this technique provides a successful means of performing resections of deep-seated lesions within the posterior fossa and may minimize the potential morbidity associated with these procedures.
8. Yacoub A, Anschuetz L, Schneider D, Wimmer W, Caversaccio M. Minimally invasive lateral endoscopic multiport approach to the infratemporal fossa: a cadaveric study. World Neurosurg. 2018;112: e489-e496. 9. Van Rompaey J, Bush C, McKinnon B, Solares AC. Minimally invasive access to the posterior cranial fossa: an anatomical study comparing a retrosigmoidal endoscopic approach to a microscopic approach. J Neurol Surg A Cent Eur Neurosurg. 2013; 74:1-6. 10. Chaichana KL, Cabrera-Aldana EE, Jusue-Torres I, Wijesekera O, Olivi A, Rahman M, et al. When gross total resection of a glioblastoma is possible, how much resection should be achieved? World Neurosurg. 2014;82:e257-265. 11. Chaichana KL, Jusue-Torres I, Navarro-Ramirez R, Raza SM, Pascual-Gallego M, Ibrahim A, et al. Establishing percent resection and residual volume thresholds affecting survival and recurrence for patients with newly diagnosed intracranial glioblastoma. Neuro Oncol. 2014;16:113-122.
14. Kelly PJ, Goerss SJ, Kall BA. The stereotaxic retractor in computer-assisted stereotaxic microsurgery. Technical note. J Neurosurg. 1988;69: 301-306. 15. Labib MA, Shah M, Kassam AB, Young R, Zucker L, Maioriello A, et al. The safety and feasibility of image-guided BrainPath-mediated transsulcul hematoma evacuation: a multicenter study. Neurosurgery. 2017;80:515-524. 16. Raza SM, Recinos PF, Avendano J, Adams H, Jallo GI, Quinones-Hinojosa A. Minimally invasive trans-portal resection of deep intracranial lesions. Minim Invasive Neurosurg. 2011;54:5-11. 17. Recinos PF, Raza SM, Jallo GI, Recinos VR. Use of a minimally invasive tubular retraction system for deep-seated tumors in pediatric patients. J Neurosurg Pediatr. 2011;7:516-521. 18. Dubey A, Yadav N, Ratre S, Parihar VS, Yadav YR. Full endoscopic vascular decompression in trigeminal neuralgia: experience of 230 patients. World Neurosurg. 2018;113:e612-e617.
Conflict of interest statement: K. L. Chaichana is a course lecturer for NICO Corporation BrainPath. Received 21 June 2018; accepted 8 August 2018
12. Cabantog AM, Bernstein M. Complications of first craniotomy for intra-axial brain tumour. Can J Neurol Sci. 1994;21:213-218. 13. Kelly PJ. Future perspectives in stereotactic neurosurgery: stereotactic microsurgical removal of deep brain tumors. J Neurosurg Sci. 1989;33: 149-154.
WORLD NEUROSURGERY -: e1-e5, - 2018
Citation: World Neurosurg. (2018). https://doi.org/10.1016/j.wneu.2018.08.049 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2018 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
e5
Minimally Invasive Resection of Intra-axial Posterior Fossa Tumors Using Tubular Retractors David Mampre, Alexandra Bechtle, Kaisorn L. Chaichana
OBJECTIVE: Posterior fossa tumor surgery is associated with a significant risk of complications, and the complications are typically more frequent compared with similar supratentorial surgeries. This study aimed to evaluate 1) the extent of resection and neurologic outcomes and 2) perioperative complications with use of minimally invasive approaches for intra-axial posterior fossa tumors from our case series.
-
METHODS: All consecutive patients who underwent nonbiopsy surgery of a posterior fossa tumor using tubular retractors and exoscopic visualization from January 2016 to May 2018 were prospectively identified and included.
-
RESULTS: During the reviewed period, 15 patients underwent resection of an intra-axial posterior fossa tumor. Eight (53%) patients were men, and the median age was 63.0 years (interquartile range: 45.0e67.5 years). The tumor was located in the cerebellar hemisphere in 11 (73%) cases, vermis in 3 (20%) cases, and middle cerebellar peduncle in 1 (7%) case. The median preoperative and postoperative lesion volumes were 21.6 cm3 (interquartile range: 10.1e33.0 cm3) and 0 cm3 (interquartile range: 0e1.2 cm3), respectively. The percent resection was 100% (92%-100%). Following surgery, 12 (80%) patients had improved and 3 (20%) patients had stable Karnofsky performance scale scores, whereas no patients had a decline in Karnofsky performance scale score postoperatively. No patients incurred other postoperative regional or medical complications.
-
posterior fossa intra-axial tumors with relatively high efficacy and low morbidity.
INTRODUCTION
P
osterior fossa surgery is associated with a significant risk of complications, and the complications are typically more frequent compared with similar supratentorial surgeries.1-3 In large institutional studies, this complication rate is approximately 25%e40%, and the major complications include cerebrospinal fluid (CSF) leaks and wound infections, among others.1-3 In addition, these surgeries are associated with significantly more pain likely because of the extensive muscle dissection, larger bony openings relative to lesion size, and entry into CSF spaces.4 Minimally invasive approaches may be associated with less morbidity and pain because the openings are smaller, involve less muscle dissection, potentially avoid CSF spaces, and have shorter durations.5-7 However, studies using minimally invasive approaches for posterior fossa intra-axial pathology are primarily limited to cadaveric studies.8,9 For the past couple of years, we have used minimally invasive approaches for posterior fossa tumors, and we hypothesize that this method is associated with high efficacy and low morbidity. The primary objectives of the present study were to evaluate extent of resection and neurologic outcomes, and the secondary objective was to evaluate perioperative complications with minimally invasive approaches for intra-axial posterior fossa tumors from our case series. MATERIALS AND METHODS
-
CONCLUSIONS: We demonstrated the possible efficacy of a minimally invasive approach with the use of tubular retractors and exoscopic visualization for resecting
Patient Selection This study received institutional review board approval (#72892). All consecutive patients who underwent nonbiopsy surgery
Key words Exoscope - Keyhole - Minimally invasive - Posterior fossa - Tubular retractor - Tumor
Department of Neurosurgery, Mayo Clinic, Jacksonville, Florida, USA
-
To whom correspondence should be addressed: Kaisorn L. Chaichana, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2018). https://doi.org/10.1016/j.wneu.2018.08.049 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com
Abbreviations and Acronyms CSF: Cerebrospinal fluid IQR: Interquartile range KPS: Karnofsky performance scale
WORLD NEUROSURGERY -: e1-e5, - 2018
1878-8750/$ - see front matter ª 2018 Elsevier Inc. All rights reserved.
www.WORLDNEUROSURGERY.org
e1
ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
performed by the senior author (K.L.C.) for a posterior fossa tumor using tubular retractors with exoscopic visualization from January 2016 to May 2018 were prospectively identified and included in this case series. The collected variables were age, sex, lesion location, preoperative and postoperative neurologic function and functional status (Karnofsky performance scale [KPS] score for tumor cases), preoperative and postoperative lesion volume, and follow-up duration. KPS scores were recorded immediately preoperatively, on discharge, and at subsequent follow-up visits. Preoperative and postoperative lesion volume were measured as previously described using semiautomated programming.10,11 For tumor cases, the tumor volumes were measured using T1-weighted magnetic resonance imaging with gadolinium for contrast-enhancing tumors and T2-weighted magnetic resonance imaging for nonecontrast-enhancing tumors. General Treatment Strategy Patients who presented with deep-seated, intra-axial posterior fossa lesions within the hemisphere, vermis, or cerebellar peduncles were considered for nonbiopsy surgical resection using tubular retractors. A tubular retractor was chosen to allow access to deep-seated lesions to minimize the need for conventional large
Figure 1. Example of a posterior fossa case with use of a tubular retractor. (A) A small 3-cm craniotomy is done. (B) Dura mater is opened in a cruciate fashion. (C) The cortex is cauterized in a linear fashion parallel to the folia.
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craniotomies, extensive white matter dissection, and use of retractor blades. Typically, these lesions were not superficially located (obviating the need for a tubular retractor), were not larger than 4.5 cm for tumor cases, were not primarily based in the brainstem, and were difficult to access using an extra-axial route. The goal of each case was to achieve maximal resection without causing significant or progressive neurologic deficit. Patients typically underwent preoperative imaging for intraoperative navigation purposes within 48 hours of surgery. In the operating room, the patient was placed prone on chest rolls with the pressure points padded. The patient was kept in a neutral position to help with intraoperative orientation. The trajectory toward the lesion was planned preoperatively and was chosen based on minimizing the potential morbidity associated with accessing the lesion. This was typically done through the cerebellar hemisphere (Figure 1). Resection was aimed at the contrast-enhancing portion of the lesion and not fluid attenuated inversion recovery changes for tumor cases. Per hospital protocol, patients were given 2 g cefazolin intravenously within 30 minutes of incision and 1 g every 8 hours for 24 hours postoperatively. For patients with penicillin allergies, 600 mg clindamycin was given intravenously within 30 minutes of incision, and 600 mg was given every 8 hours for 24 hours
(D) Ultrasound is used to guide the trajectory of the tubular retractor and to assess lesion resection. (E) The tumor is removed en bloc through the tubular retractor.
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2018.08.049
ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
postoperatively. Based on intraoperative navigation and surgical planning, a 3-cm linear skin incision was made overlying the planned trajectory. An approximately 2-cm craniotomy was made, and the dura mater was then opened in a cruciate fashion. A 0- or 90degree exoscope (Vitom; KARL STORZ-Endoscopy America, Inc., El Segundo, California, USA) attached to a pneumatic arm (UniARM; Mitaka USA, Inc., Park City, Utah, USA) was used to provide visualization and magnification through the tubular retractor, as previously described.5-7 The cerebellar hemisphere or vermis was cauterized parallel to the folia, and then the preselected tubular retractor (BrainPath; NICO Corporation, Indianapolis, Indiana, USA) was passed with the aid of frameless stereotactic guidance to reach the most superficial component for tumor cases. For smaller or deeper lesions, an ultrasound probe (Hitachi Aloka Medical America, Wallingford, Connecticut, USA) was used to establish appropriate trajectory and lesion localization. Once the lesion was accessed, the lesion was resected using suction, tissue-biting (Myriad; NICO Corporation), or bipolar cautery. Following resection, the retractor was withdrawn, and the dura, bone, and skin were closed in standard fashion. Postoperative magnetic resonance imaging was performed 1e2 days after surgery.
RESULTS The patients who were operated on using a tubular retractor and exoscopic visualization are summarized in Table 1 and Figure 2. During the reviewed period, 15 patients underwent resection of a posterior fossa tumor. Eight (53%) patients were men, and the median (interquartile range [IQR]) age of all patients was 63 years
(IQR: 45e67.5 years). The tumor was located in the cerebellar hemisphere in 11 (73%) cases, vermis in 3 (20%) cases, and middle cerebellar peduncle in 1 (7%) case. The median preoperative lesion volume was 21.6 cm3 (IQR: 10.1e33.0 cm3). The median preoperative KPS score was 70 (IQR: 60e70). The major presenting symptoms were headaches, nausea, and vomiting in 12 (85%) patients; ataxia and gait problems in 10 (60%) patients; and mental status changes in 5 (33%) patients. Following surgery, the median postoperative lesion volume was 0 cm3 (IQR: 0e1.2 cm3), and median percent resection was 100% (IQR: 92%e100%). Gross total resection was achieved in 12 (80%) cases. The remaining 3 cases were limited by involvement of the brainstem in 2 (13%) and tentorium in 1 (7%). There were no cases with hemostasis problems, and no cases with notable postoperative cavity hemorrhages. At 1 month postoperatively, median postoperative KPS score was 80 (IQR: 70e95). Following surgery, 12 (80%) patients had improved KPS scores, 3 (20%) patients had stable KPS scores, and no patients had a decline in KPS score. No patients experienced postoperative medical complications, including infection, CSF leak, pneumonia, deep vein thrombosis/ pulmonary embolism, sepsis, or seizures. There were no reports of worsened deficits, including motor weakness, language deficits, cranial nerve problems, and balance issues. The median follow-up duration was 6.4 months (IQR: 4.2e9.6 months) after surgery.
DISCUSSION In this case series of 15 patients who underwent minimally invasive resection of a posterior fossa intraparenchymal lesion, most
Table 1. Summary of Patients Who Underwent Resection of a Posterior Fossa Intra-axial Neoplasm Using Tubular Retractors with Exoscopic Visualization Patient
Age (Years)/Sex
Location
Pathology
Percent Resection
Preop KPS Score
Postop KPS Score
Improved KPS Score
1
78/F
Hemisphere
Metastatic
100%
30
90
Improved
2
49/F
MCP
Cavernoma
100%
60
100
Improved
3
23/F
Hemisphere
Hemangioblastoma
100%
80
100
Improved
4
69/F
Hemisphere
Metastatic
100%
60
70
Improved
5
63/M
Vermis
Metastatic
100%
70
80
Improved
6
51/M
Hemisphere
Metastatic
84%
70
70
Stable
7
32/F
Hemisphere
Metastatic
100%
90
100
Improved
8
37/M
Hemisphere
Cavernoma
100%
80
100
Improved
9
69/M
Vermis
Metastatic
100%
70
70
Stable
10
46/M
Vermis
Metastatic
90%
50
70
Improved
11
66/M
Hemisphere
Metastatic
92%
70
70
Stable
12
65/F
Hemisphere
Metastatic
100%
40
70
Improved
13
44/M
Hemisphere
Metastatic
100%
70
90
Improved
14
66/M
Hemisphere
Hemangioblastoma
100%
70
80
Improved
15
72/M
Hemisphere
Metastatic
89%
60
80
Improved
Preop, preoperative; KPS, Karnofsky performance scale; Postop, postoperative; F, female; MCP, middle cerebellar peduncle, M, male.
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ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
Figure 2. Cerebellar hemisphere hemangioblastoma. (AeC) A 19-year-old woman presented with nausea, vomiting, and ataxia and was found to have a cystic contrast-enhancing lesion in the right cerebellar hemisphere with significant vasogenic edema. (A) Axial T1-weighted magnetic resonance imaging with contrast enhancement. (B) Axial T2-weighted
patients did well after surgery. The median percent tumor resection was 100%; 85% of patients underwent gross total resection, whereas the remaining 15% had resection limited by brainstem or tentorial involvement. Of patients, 100% had improved and/or stable KPS score, whereas 85% improved, and no patients had a decline. At last follow-up, there were no incidences of infection, CSF leak, or other medical complications. Posterior fossa surgery can be associated with significant morbidity and mortality.1-3 Dubey et al.1 evaluated 500 patients operated on over a 10-year period at a single institution and found that 159 (31.8%) patients had complications. The complications included CSF leak in 65 (13%), meningitis in 46 (9.2%), and wound infection in 35 (7%) among patients who underwent resection of cerebellopontine angle tumors, microvascular decompression, cerebellar lesions, and Chiari malformations, among others. Brell et al.3 studied complications associated with intra-axial tumors in 200 patients with gliomas and metastases. Of patients 27.5% had complications, and
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imaging. (C) Sagittal T1-weighted imaging with contrast enhancement. (DeF) Patient underwent gross total resection with a tubular retractor and exoscopic visualization. (D) Axial T1-weighted imaging with contrast enhancement. (E) Axial T2-weighted imaging. (F) Coronal T1-weighted imaging with contrast enhancement.
infratentorial tumor location, previous radiation therapy, and reoperations were each independently associated with regional complications. Similarly, Cabantog and Bernstein12 reported a single surgeon’s experience with 207 consecutive patients, where the overall complication rate was 25.1%. They found that infratentorial location (44% vs. 25%) was associated with higher complications regardless of histology. A method of accessing deep-seated lesions is with the use of tubular retractors that provide a protected corridor with circumferential retraction.5-7,13-17 Early use of tubular retractors was for supratentorial lesions in the basal ganglia and thalamus.13,14 More recently, these approaches have been used for intracerebral hematomas, gliomas, and biopsies in deep-seated locations.5-7,15 The use of minimally invasive intracranial surgery may decrease the morbidity associated with posterior fossa intra-axial surgery. The principle of minimally invasive surgery is to be atraumatic, preserve the surrounding tissue, and still resect the lesion. This may allow for smaller incisions, less muscle dissection, smaller
WORLD NEUROSURGERY, https://doi.org/10.1016/j.wneu.2018.08.049
ORIGINAL ARTICLE DAVID MAMPRE ET AL.
MINIMALLY INVASIVE TUMOR RESECTION
craniotomies, and less extensive white matter dissection.5-7 However, studies devoted to these techniques with posterior fossa pathology are limited to extra-axial pathology (i.e., microvascular decompression) and cadaveric studies.8,9,18 In the present study, there was no reported morbidity, and there was high efficacy with this approach. Among these patients, no patients worsened, whereas 12 (80%) and 3 (20%) had improved and stable KPS scores following surgery, respectively. Gross total resection was achieved in 12 (80%). All patients had deep-seated lesions and therefore represent challenging intra-axial posterior fossa pathology cases. This study is the first to our knowledge to describe the efficacy of using minimally invasive approaches for posterior fossa intra-axial surgery and provides an alternative to traditional open approaches. This approach may minimize the morbidity associated with infratentorial surgery, while maintaining extent of resection. In this study, we show that extensive resection can be maintained for tumors with low morbidity. Moreover, gross total resection was achieved in most patients, and cases without gross total resection were limited by eloquent or critical neurovascular involvement. This study has some limitations. The study was not designed to evaluate if this technique was better compared with conventional techniques in regard to surgical time, postoperative pain, complications, and extent of resection. The purpose of this study was to serve as a proof-of-principle to demonstrate that these
2. Hadanny A, Rozovski U, Nossek E, Shapira Y, Strauss I, Kanner AA, et al. Craniectomy versus craniotomy for posterior fossa metastases: complication profile. World Neurosurg. 2016;89: 193-198. 3. Brell M, Ibanez J, Caral L, Ferrer E. Factors influencing surgical complications of intra-axial brain tumours. Acta Neurochir (Wien). 2000;142: 739-750. 4. Beretta E, Vetrano IG, Curone M, Chiapparini L, Furlanetto M, Bussone G, et al. Chiari malformation-related headache: outcome after surgical treatment. Neurol Sci. 2017;38:95-98. 5. Gassie K, Wijeseekera O, Chaichana KL. Minimally invasive tubular retractor-assisted biopsy and resection of subcortical intra-axial gliomas and other neoplasms [e-pub ahead of print]. J Neurosurg Sci. https://doi.org/10.23736/S0390-5616. 18.04466-1. Accessed June 15, 2018. 6. Iyer R, Chaichana KL. Minimally invasive resection of deep-seated high-grade gliomas using tubular retractors and exoscopic visualization. J Neurol Surg A Cent Eur Neurosurg. 2018;79:330-336. 7. Jackson C, Gallia GL, Chaichana KL. Minimally invasive biopsies of deep-seated brain lesions using tubular retractors under exoscopic
CONCLUSIONS Surgery in the posterior fossa, regardless of pathology, is associated with a higher risk of morbidity and mortality. The standard approaches involve large incisions, extensive muscle dissection, and wide craniectomies and are associated with a multitude of complications. We describe the use of tubular retractors with exoscopic visualization as a minimally invasive approach to resect these intra-axial lesions with relatively high efficacy and low morbidity. This approach using tubular retractors in this case series was associated with extensive resection without associated morbidity.
visualization. J Neurol Surg A Cent Eur Neurosurg. 2017;78:588-594.
REFERENCES 1. Dubey A, Sung WS, Shaya M, Patwardhan R, Willis B, Smith D, et al. Complications of posterior cranial fossa surgery—an institutional experience of 500 patients. Surg Neurol. 2009;72: 369-375.
techniques can be used for intra-axial posterior fossa surgery. However, we acknowledge that our small sample size limits the ability to perform statistical analyses and prevents generalizability. Larger and/or randomized studies comparing this technique with standard techniques with longer follow-up are needed to evaluate survival outcomes. In addition, the short-term follow-up of the patients in this series prevents a detailed evaluation of possible long-term effects and/or neurologic deficits. Nevertheless, we believe this technique provides a successful means of performing resections of deep-seated lesions within the posterior fossa and may minimize the potential morbidity associated with these procedures.
8. Yacoub A, Anschuetz L, Schneider D, Wimmer W, Caversaccio M. Minimally invasive lateral endoscopic multiport approach to the infratemporal fossa: a cadaveric study. World Neurosurg. 2018;112: e489-e496. 9. Van Rompaey J, Bush C, McKinnon B, Solares AC. Minimally invasive access to the posterior cranial fossa: an anatomical study comparing a retrosigmoidal endoscopic approach to a microscopic approach. J Neurol Surg A Cent Eur Neurosurg. 2013; 74:1-6. 10. Chaichana KL, Cabrera-Aldana EE, Jusue-Torres I, Wijesekera O, Olivi A, Rahman M, et al. When gross total resection of a glioblastoma is possible, how much resection should be achieved? World Neurosurg. 2014;82:e257-265. 11. Chaichana KL, Jusue-Torres I, Navarro-Ramirez R, Raza SM, Pascual-Gallego M, Ibrahim A, et al. Establishing percent resection and residual volume thresholds affecting survival and recurrence for patients with newly diagnosed intracranial glioblastoma. Neuro Oncol. 2014;16:113-122.
14. Kelly PJ, Goerss SJ, Kall BA. The stereotaxic retractor in computer-assisted stereotaxic microsurgery. Technical note. J Neurosurg. 1988;69: 301-306. 15. Labib MA, Shah M, Kassam AB, Young R, Zucker L, Maioriello A, et al. The safety and feasibility of image-guided BrainPath-mediated transsulcul hematoma evacuation: a multicenter study. Neurosurgery. 2017;80:515-524. 16. Raza SM, Recinos PF, Avendano J, Adams H, Jallo GI, Quinones-Hinojosa A. Minimally invasive trans-portal resection of deep intracranial lesions. Minim Invasive Neurosurg. 2011;54:5-11. 17. Recinos PF, Raza SM, Jallo GI, Recinos VR. Use of a minimally invasive tubular retraction system for deep-seated tumors in pediatric patients. J Neurosurg Pediatr. 2011;7:516-521. 18. Dubey A, Yadav N, Ratre S, Parihar VS, Yadav YR. Full endoscopic vascular decompression in trigeminal neuralgia: experience of 230 patients. World Neurosurg. 2018;113:e612-e617.
Conflict of interest statement: K. L. Chaichana is a course lecturer for NICO Corporation BrainPath. Received 21 June 2018; accepted 8 August 2018
12. Cabantog AM, Bernstein M. Complications of first craniotomy for intra-axial brain tumour. Can J Neurol Sci. 1994;21:213-218. 13. Kelly PJ. Future perspectives in stereotactic neurosurgery: stereotactic microsurgical removal of deep brain tumors. J Neurosurg Sci. 1989;33: 149-154.
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