Cranial Base Surgery Research Articles

Facial translocation surgery- a case series

Background: The complexity of cranial base surgery is a reflection of skull base anatomy as well as technical demands for maximum visualization, control of essential structures, adequate tumor resection and/or reconstruction. Facial translocation has been developed as a new approach to cranial base.

Modified Endoscopic Diving Technique without the Traditional Irrigation System in Endoscopic Cranial Base Surgery: Technical Note

We describe a modified endoscopic diving technique with an alternative irrigation system different than the one used by Locatelli etal. (CLEARVISION II, Karl Storz and Co., Tuttlingen, Germany). From January 2016 to October 2018, our senior surgeon performed the modified endoscopic diving technique in 76 endoscopic surgical procedures. Diving surgery was performed in all procedures to check the completeness of tumor resection, thus allowing for the removal of any residual tumor tissue. In the modified endoscopic diving technique, the optic system and the irrigation source are separated into 2 independent tools, allowing surgeons to point the flow on a selected structure, whereas the endoscope can be pointed in the same direction or not. Moreover, the optic system and the irrigation source can be placed at different distances. Surgeons can control the infusion pressure and the entity of the flow. The use of the modified endoscopic diving technique allows surgeons to have more settings that could be controlled and also bypasses any compatibility issues between different endoscopic systems. In addition, the reproducibility of this technique, together with the low cost of the instrumentation, could allow an easier application of the diving technique.

Long-term impact of pediatric endoscopic endonasal skull base surgery on midface growth.

Cranial base development plays a large role in anterior and vertical maxillary growth through 7 years of age, and the effect of early endonasal cranial base surgery on midface growth is unknown. The authors present their experience with pediatric endoscopic endonasal surgery (EES) and long-term midface growth. This is a retrospective review of cases where EES was performed from 2000 to 2016. Patients who underwent their first EES of the skull base before age 7 (prior to cranial suture fusion) and had a complete set of pre- and postoperative imaging studies (CT or MRI) with at least 1 year of follow-up were included. A radiologist performed measurements (sella-nasion [S-N] distance and angles between the sella, nasion, and the most concave points of the anterior maxilla [A point] or anterior mandibular synthesis [B point], the SNA, SNB, and ANB angles), which were compared to age- and sex-matched Bolton standards. A Z-score test was used; significance was set at p < 0.05. The early surgery group had 11 patients, with an average follow-up of 5 years; the late surgery group had 33 patients. Most tumors were benign; 1 patient with a panclival arteriovenous malformation was a significant outlier for all measurements. Comparing the measurements obtained in the early surgery group to Bolton standard norms, the authors found no significant difference in postoperative SNA (p = 0.10), SNB (p = 0.14), or ANB (0.67) angles. The S-N distance was reduced both pre- and postoperatively (SD 1.5, p = 0.01 and p = 0.009). Sex had no significant effect. Compared to patients who had surgery after the age of 7 years, the early surgery group demonstrated no significant difference in pre- to postoperative changes with regard to S-N distance (p = 0.87), SNA angle (p = 0.89), or ANB angle (p = 0.14). Lesion type (craniopharyngioma, angiofibroma, and other types) had no significant effect in either age group. Though our cohort of patients with skull base lesions demonstrated some abnormal measurements in the maxillary-mandibular relationship before their operation, their postoperative cephalometrics fell within the normal range and showed no significant difference from those of patients who underwent operations at an older age. Therefore, there appears to be no evidence of impact of endoscopic endonasal skull base surgery on craniofacial development within the growth period studied.

Contribution of Augmented Reality to Minimally Invasive Computer-Assisted Cranial Base Surgery.

Cranial base procedures involve manipulation of small, delicate and complex structures in the fields of otology, rhinology, neurosurgery and maxillofacial surgery. Critical nerves and blood vessels are in close proximity of these structures. Augmented reality is an emerging technology that can revolutionize the cranial base procedures by providing supplementary anatomical and navigational information unified on a single display. However, the awareness and acceptance of possibilities of augmented reality systems in cranial base domain is fairly low. This article aims at evaluating the usefulness of augmented reality systems in cranial base surgeries and highlights the challenges that current technology faces and their potential solutions. A technical perspective about different strategies employed in development of an augmented realty system is also presented. The current trend suggests an increase in interest towards augmented reality systems that may lead to safer and cost-effective procedures. However, several issues need to be addressed before it can be widely integrated into routine practice.

Endoscopic Assisted Microscopic Skull Base Surgery

Background: Over the last decade skull base surgery has been significantly progressed because of the obvious improvements in imaging, anesthetic, surgical techniques as well as the advancement of microsurgical instruments. However, the anatomical complexity of skull base makes dealing with lesions in such area a “surgical challenge”. That’s why looking for alternative methods is always needed. Meanwhile there have been significant advances in the field of cranial base surgery with the help of endoscopic techniques to manage such lesions. Objective: To demonstrate the value of endoscope-assisted microsurgical technique for resection of skull base tumors. Patients and Methods: Twenty patients had skull base tumors were operated through Endoscopic-assisted microscopic skull base surgery technique at Al-Azhar University & Mansoura International Hospital between 2015 to 2017 using a rigid endoscope for inspection of tumor boundaries and neighboring vascularity in addition to confirm the extent of resection. Tumor resection was tried in all cases. Intra-operative resection rate and post-operative radiological outcomes were assessed. Results: Total resection was done in 10 patients (50%). Subtotal resection was done in the other 10 cases due to excessive bleeding and adhesions of the tumors with vascular structures. Conclusion: Endoscopic-assisted microsurgical approach is a reliable, safe and effective option for adequate surgical resection of skull base tumors. The technique allowed proper inspection of the tumor relations and vascularity, detection of any residual portions, providing better chance for gross total resection with minimal tissue damage or vascular injury as well as convenient clinical outcome.

Endoscopic Assisted Microscopic Skull Base Surgery

Background: Over the last decade skull base surgery has been significantly progressed because of the obvious improvements in imaging, anesthetic, surgical techniques as well as the advancement of microsurgical instruments. However, the anatomical complexity of skull base makes dealing with lesions in such area a “surgical challenge”. That’s why looking for alternative methods is always needed. Meanwhile there have been significant advances in the field of cranial base surgery with the help of endoscopic techniques to manage such lesions. Objective: To demonstrate the value of endoscope-assisted microsurgical technique for resection of skull base tumors. Patients and Methods: Twenty patients had skull base tumors were operated through Endoscopic-assisted microscopic skull base surgery technique at Al-Azhar University & Mansoura International Hospital between 2015 to 2017 using a rigid endoscope for inspection of tumor boundaries and neighboring vascularity in addition to confirm the extent of resection. Tumor resection was tried in all cases. Intra-operative resection rate and post-operative radiological outcomes were assessed. Results: Total resection was done in 10 patients (50%). Subtotal resection was done in the other 10 cases due to excessive bleeding and adhesions of the tumors with vascular structures. Conclusion: Endoscopic-assisted microsurgical approach is a reliable, safe and effective option for adequate surgical resection of skull base tumors. The technique allowed proper inspection of the tumor relations and vascularity, detection of any residual portions, providing better chance for gross total resection with minimal tissue damage or vascular injury as well as convenient clinical outcome.

O-arm in Endonasal Endoscopic Cranial Base Surgery: Technical Note on Initial Feasibility

In transsphenoidal endoscopic cranial base surgery, a precise navigational support may be crucial. This is particularly evident when tumors extend to the parasellar region or in recurrent tumors whereas normal anatomy has been altered by previous surgery/radiotherapy. Previous unsatisfactory experiences with various navigation techniques in this type of surgery encouraged us to perform an endoscopic endonasal approach with an O-arm (Medtronic, Inc., Minneapolis, Minnesota, USA) assisted technique for the surgical treatment of 4 patients affected respectively by an orbital tumor and 3 cases of relapse of nonfunctioning pituitary adenoma, 1 of them localized in the infrasellar-clival region. The system O-arm-StealthStation allows for merging intraoperative bone 3-D acquisition with preoperative computed tomography/magnetic resonance imaging and provides the surgeon with an extremely reliable operative navigational tool. This is the first report of an O-arm-assisted endoscopic surgery for cranial base tumors. Here we report on the feasibility and usefulness of such a new application of the O-arm: technical details, setting of the operating room, advantages, and limits of the method are also described. Our overall impression, considering the limited number of patients, is that use of the O-arm may be successfully extended to selected cases of cranial base tumors operated through an endoscopic endonasal approach.

Comparison of Occipital Condyle Morphometry in Various Populations with Respect to Skull Base Surgery

Background: The craniovertebral junction is made up of the occiput, upper two cervical vertebrae. Occipital condyle is one the landmarks on the skull base. Morphometric values of these condyles in a specific population is to be known by surgeons to deal with pathologies affecting the cranial base without disturbing the neurovascular structures by doing appropriate condylectomy and to ensure occipito-cervical fusion in case of instability. Methods: The study was performed by comparing the morphometric values of occipital condyles with other populations (Greek, Turkish, Korean, Chinese, American, European and Indian). The data regarding the morphometric values of occipital condyles was taken from our previously published article with a sample of hundred occipital condyles of unsexed dry human skulls of unknown age and compared with the studies of other population. The measurements compared were the length, breadth and thickness of the occipital condyle, intercondylar distance in anterior, middle and posterior parts of the occipital condyles, the angle of the occipital condyle to the sagittal plane and coronal planes and shape of the occipital condyles. Results: Most of the morphometric values of OC in South Indian were lesser than the other populations like breadth, thickness,anterior intercondylar distance, posterior intercondylar distance, angle of the occipital condyle to the sagittal plane. Conclusion: This information has to borne in mind while performing surgical procedures like occipito-cervical screw fixation, condylar drilling in cranial base surgery in South Indian population.

Preoperative Exposure of Sigmoid Sinus Trajectory in Posterolateral Cranial Base Approaches Using a New Landmark Through a Neurosurgical Perspective.

The location of burr holes in posterolateral cranial base approaches should be appropriate to provide an adequate operative field, and surgical freedom is crucial for bone window opening. The aim of this study was to search for more convenient and easily detectable landmarks in comparison with current landmarks in posterolateral cranial base surgery. Twenty 3-dimensional reconstructed head and neck computed tomography angiography images (group 1) and 20 cadaver heads (group 2) were evaluated. An imaginary line connecting the angle of the mandible and the mastoid tip was extended upward. A second line passing through the lateral edge of the zygomatic arch was also extended posteriorly. The authors examined if the first line met with the sigmoid sinus throughout its course and determined the location of the intersection point of these 2 lines relative to the sigmoid-transverse sinus junction. The intersection point did not correspond to the sinus region in 3 images from group 1 and 4 specimens from group 2. The matching of the mandibula-mastoid line trajectory with the sigmoid sinus course was unacceptable in 4 images and 5 cadavers. For venous anatomy preservation and anatomic skull base fossa orientation during posterolateral cranial base approaches, upward extension of the mandibula-mastoid line can be a proper landmark for surgical planning in this region. The authors' proposed superficial anatomical line and intersection point over the skull could be used as a reliable indicator for the external projection of the sigmoid sinus and an appropriate initial burr-hole location.

The Endoscopic Buccal Fat Pad Flap for Closure of Skull Base Defects: A Report of 5 Cases.

To demonstrate the clinical utility of the buccal fat pad flap (BFPF) for closing a variety of skull base defects. A retrospective chart review of 5 consecutive patients who underwent endoscopic cranial base surgery with endoscopic harvest of BFPF pedicled along the internal maxillary artery for reconstruction of the skull base between October 2013 and November2014. All 5 patients had complete take of the BFPFs with mucosalization on postoperative follow-up with no reported complications or cerebrospinal fluid leak. This is the first report on the application of endoscopic BFPF. Our experience suggests that this recently described flap is viable and a useful addition to the armamentarium of the skull base surgeon.

138 Endoscopic Endonasal Skull Base Surgery in Pediatric Patients and Impact on Midface Growth

Abstract INTRODUCTION Cranial base development plays a large role in anterior and vertical maxillary growth through age 7, and the effect of early endonasal cranial base surgery on midface growth is unknown. We present our experience with pediatric endoscopic endonasal surgery and long-term midface growth. METHODS This is a retrospective review (2000-2016). Pediatric patients were grouped by age at first endoscopic endonasal skull base surgery (&lt;7 yo and &gt;7 yo). Included patients had both pre- and post-operative (&gt;1 yr) imaging. Radiologists performed measurements (Sella-Nasion distance and angles from S-N to maxilla and mandible (SNA, SNB, ANB)), which were compared to age- and sex-matched Bolton standards. Z score test was used; significance was set at P &lt; 0.05. RESULTS &gt;The &lt;7 yo group had 11 patients, averaging follow-up of 5 yrs; the &gt;7 yo group had 33 patients. Most tumors were benign; one patient with a panclival AVM was a significant outlier for all measurements. Comparing the &lt;7 yo group to Bolton standard norms, there was no significant difference in post-operative SNA (P = 0.10), SNB (P = 0.14), or ANB (0.67). SN distance was reduced both pre- and post-operatively (SD = 1.5, P = 0.01 and P = 0.009). Sex had no significant effect. Compared to patients who had surgery in the &gt;7 yo group, the &lt;7 yo group demonstrated no significant difference in pre- to post-operative changes with regard to S-N (P = 0.87), SNA (P = 0.89), and ANB (P = 0.14). Tumor type (craniopharyngioma, angiofibroma, and other types) had no significant effect in either age group. CONCLUSION Though our cohort of patients with skull base tumors demonstrate some abnormal measurements before their operation, their post-operative cephalometrics fall within normal standard deviations and generally have no significant difference compared to patients who underwent operations at an older age. Therefore, there appears to be no evidence of impact of endoscopic endonasal skull base surgery on craniofacial development within the growth period studied.

The Learning Curve in Endoscopic Endonasal Resection of Craniopharyngiomas

OBJECTIVE There is a paucity of literature regarding the learning curve associated with performing endoscopic endonasal cranial base surgery. The purpose of this study was to determine to what extent a learning curve might exist for endoscopic endonasal resection in cases of craniopharyngiomas. METHODS A retrospective review was performed for all endoscopic endonasal craniopharyngioma resections performed at Thomas Jefferson University from 2005 to 2015. To assess for a learning curve effect, patients were divided into an early cohort (2005-2009, n = 20) and a late cohort (2010-2015, n = 23). Preoperative demographics, clinical presentation, imaging characteristics, extent of resection, complications, tumor control, and visual and endocrine outcomes were obtained. Categorical variables and continuous variables were compared using a 2-sided Fisher's exact test and t-test, respectively. RESULTS Only the index operation performed at the authors' institution was included. There were no statistically significant differences between early and late cohorts in terms of patient age, sex, presenting symptoms, history of surgical or radiation treatment, tumor size or consistency, hypothalamic involvement, or histological subtype. The rate of gross-total resection (GTR) increased over time from 20% to 65% (p = 0.005), and the rate of subtotal resection decreased over time from 40% to 13% (p = 0.078). Major neurological complications, including new hydrocephalus, meningitis, carotid artery injury, or stroke, occurred in 6 patients (15%) (8 complications) in the early cohort compared with only 1 (4%) in the late cohort (p = 0.037). CSF leak decreased from 40% to 4% (p = 0.007). Discharge to home increased from 64% to 95% (p = 0.024). Visual improvement was high in both cohorts (88% [early cohort] and 81% [late cohort]). Rate of postoperative panhypopituitarism and permanent diabetes insipidus both increased from 50% to 91% (p = 0.005) and 32% to 78% (p = 0.004), which correlated with a significant increase in intentional stalk sacrifice in the late cohort (from 0% to 70%, p < 0.001). CONCLUSIONS High rates of near- or total resection and visual improvement can be achieved using an endoscopic endonasal approach for craniopharyngiomas. However, the authors did find evidence for a learning curve. After 20 cases, they found a significant decrease in major neurological complications and significant increases in the rates of GTR rate and discharge to home. Although there was a large decrease in the rate of postoperative CSF leak over time, this was largely attributable to the inclusion of very early cases prior to the routine use of vascularized nasoseptal flaps. There was a significant increase in new panhypopituitarism and diabetes insipidus, which is attributable to increase rates of intentional stalk sacrifice.

Potential Effect of Leukocyte-Platelet-Rich Fibrin in Bone Healing of Skull Base: A Pilot Study.

Background Reconstruction of surgical defects following cranial base surgery is challenging. Others have demonstrated that leukocyte-platelet-rich fibrin (L-PRF) stimulates tissue healing and bone regeneration. However, these studies have addressed mostly maxillofacial surgical wounds. Objective The objective of this study was to assess the possible adjuvant role of L-PRF in inducing neoossification of the surgical bone defect in anterior skull base surgery. Methods We identified patients who had undergone an endoscopic endonasal surgery of the anterior skull base in which L-PRF membranes were used for the reconstruction of the bone defect and who were followed up with postoperative CT scans. CT findings were then correlated with baseline scans and with the CT scans of a patient who had undergone imaging and histologic analysis after maxillofacial surgery in which L-PRF was used and in which we demonstrated bone formation. Results Five patients fulfilled the inclusion criteria. In four patients, the CT scan demonstrated closure of the bony defect by neoosteogenesis; however, the bone appeared less dense than the surrounding normal bone. A comparison with the control patient yielded similar radiological features. Conclusion This case series suggests that L-PRF may induce bone healing and regeneration at the surgical site defect. Multi-institutional studies with a larger series of patients are required to confirm this possibility.

A Technically Simple and Safe Method for Preparing an Anterior Pericranial Flap Using Saline Injection into the Subgaleal Space: A Technical Note.

Cranial defects following anterior cranial base surgery have been frequently reconstructed using the pericranial flap. We present a simple technique for preparing the flap using injection of saline into the subgaleal space. We inserted a 20-gauge needle perpendicular to 8-10 spots in the frontal area and injected 5-7 mL of saline at each spot 10 minutes before skin incision. Distinctive swelling of the scalp was then observed. After the scalp was incised, the layers were dissected with a monopolar electrocautery device. The layer containing saline allowed us to better localize its exact position and harvest the flap without injury. Dissection in the subgaleal plane was performed mainly using the tip of a surgical blade. After the periosteum was stripped from the calvaria, the flap that had been considerably thickened by saline injection was harvested. Because pericranium thickness in the frontal areas is reported to be thinner than in other areas, a beginning neurosurgeon may have difficulty harvesting an anteriorly based flap of sufficient size. The technique presented here can help increase awareness of the subgaleal layer, facilitate the dissection process, and reduce additional tissue injury resulting from electrocautery manipulation.

The learning curve in endoscopic endonasal resection of craniopharyngiomas.

OBJECTIVE There is a paucity of literature regarding the learning curve associated with performing endoscopic endonasal cranial base surgery. The purpose of this study was to determine to what extent a learning curve might exist for endoscopic endonasal resection in cases of craniopharyngiomas. METHODS A retrospective review was performed for all endoscopic endonasal craniopharyngioma resections performed at Thomas Jefferson University from 2005 to 2015. To assess for a learning curve effect, patients were divided into an early cohort (2005-2009, n = 20) and a late cohort (2010-2015, n = 23). Preoperative demographics, clinical presentation, imaging characteristics, extent of resection, complications, tumor control, and visual and endocrine outcomes were obtained. Categorical variables and continuous variables were compared using a 2-sided Fisher's exact test and t-test, respectively. RESULTS Only the index operation performed at the authors' institution was included. There were no statistically significant differences between early and late cohorts in terms of patient age, sex, presenting symptoms, history of surgical or radiation treatment, tumor size or consistency, hypothalamic involvement, or histological subtype. The rate of gross-total resection (GTR) increased over time from 20% to 65% (p = 0.005), and the rate of subtotal resection decreased over time from 40% to 13% (p = 0.078). Major neurological complications, including new hydrocephalus, meningitis, carotid artery injury, or stroke, occurred in 6 patients (15%) (8 complications) in the early cohort compared with only 1 (4%) in the late cohort (p = 0.037). CSF leak decreased from 40% to 4% (p = 0.007). Discharge to home increased from 64% to 95% (p = 0.024). Visual improvement was high in both cohorts (88% [early cohort] and 81% [late cohort]). Rate of postoperative panhypopituitarism and permanent diabetes insipidus both increased from 50% to 91% (p = 0.005) and 32% to 78% (p = 0.004), which correlated with a significant increase in intentional stalk sacrifice in the late cohort (from 0% to 70%, p < 0.001). CONCLUSIONS High rates of near- or total resection and visual improvement can be achieved using an endoscopic endonasal approach for craniopharyngiomas. However, the authors did find evidence for a learning curve. After 20 cases, they found a significant decrease in major neurological complications and significant increases in the rates of GTR rate and discharge to home. Although there was a large decrease in the rate of postoperative CSF leak over time, this was largely attributable to the inclusion of very early cases prior to the routine use of vascularized nasoseptal flaps. There was a significant increase in new panhypopituitarism and diabetes insipidus, which is attributable to increase rates of intentional stalk sacrifice.

Free Temporalis Muscle Fascia Transplant as a Reconstructive Material in Cranial Base Surgery

Free Temporalis Muscle Fascia Transplant as a Reconstructive Material in Cranial Base Surgery

Different treatments of maxillary and mandible in management of para-pharynx and cranial base surgery

Different treatments of maxillary and mandible in management of para-pharynx and cranial base surgery

Minimizing Nasal Trauma in Endoscopic Anterior Cranial Base Surgery: Preservation of Both Middle Turbinates

Objective: To report on the feasibility as well as the benefits of middle turbinate preservation while maintaining sufficient access for endoscopic anterior cranial base surgery.

Endoscopic Nasoseptal Flap Preservation Approaches to the Cranial Base: An Update to the Jefferson Approach

Introduction: The pedicled nasoseptal flap (NSF) is the mainstay for closure after endoscopic anterior cranial base surgery. The NSF is not necessary for repair of all skull base defects as CSF leaks are not always encountered intra-operatively like in the case of pituitary surgery. However, preservation of the NSF is important as it may be required for future use. We present an update to the Jefferson Approach that includes five approaches that protect one or both NSF pedicles while allowing adequate exposure of the cranial base for tumor resection.

Identification of Sex of Human Skull from its Base

Identification of a person from skeleton is very important. Bones of skeleton show sexual differences. Skull is one of part of skeleton which shows sexual differences in various parameters. In present study, 150 adult skulls were studied for 12 parameters. Out of 12 parameters, palatal breadth, combined area of foramen ovale, combined area of carotid canal and axial length of occipital condyles are found to be significant. The measurements are useful to identify the sex of an individual and also in cranial base surgery.