How to Choose? Endoscopic Skull Base Reconstructive Options and Limitations

As endoscopic skull base resections have advanced, appropriate reconstruction has become paramount. The reconstructive options for the skull base include both avascular and vascular grafts. We review these and provide an algorithm for endoscopic skull base reconstruction. One hundred and sixty-six skull base dural defects, reconstructed with an endonasal vascular flap, were examined. As an adjunct, avascular reconstruction techniques are discussed to illustrate all options for endonasal skull base reconstruction. Cerebrospinal fluid (CSF) leak rates are also discussed. Small CSF leaks may be successfully repaired with various avascular grafting techniques. Endoscopic endonasal approaches (EEAs) to the skull base often have larger dural defects with high-flow CSF leaks. Success rates for some EEA procedures utilizing avascular grafts approach 90%, yet in high-flow leak situations, success rates are much lower (50 to 70%). Defect location and complexity guides vascularized flap choice. When nasoseptal flaps are unavailable, anterior/sellar defects are best managed with an endoscopically harvested pericranial flap, whereas clival/posterior defects may be reconstructed with an inferior turbinate or temporoparietal flap. An endonasal skull base reconstruction algorithm was constructed and points to increased use of various vascularized reconstructions for more complex skull base defects.     

Inaccurate Assessments of Anterior Cranial Base Malignancy Following Nasoseptal Flap Reconstruction

Objective The nasoseptal flap (NSF) provides vascularized tissue for repair of skull base defects of various etiologies. However, the NSF repair after skull base resection for anterior cranial base malignancies may demonstrate radiologic findings confusing for recurrent or residual disease on postoperative surveillance imaging. The objective of the current study was to review neuroradiologic misinterpretations of NSF reconstruction following anterior cranial base malignancies. Methods A multicenter review of patients reconstructed with the NSF after endoscopic resection of anterior cranial base malignancies from 2008 to 2013 was performed. Data were collected regarding etiology, surgical technique, locoregional control, and postoperative radiologic assessments. Only patients with at least one postoperative surveillance scan with inaccurate assessment of residual or recurrent malignancy were included in the study. Results Over 5 years, 13 patients were identified who had erroneous reporting of malignancy due to NSF reconstruction. On average, two neuroradiologists interpreted the NSF as persistent or recurrent malignancy over this time period (range: 1–7). The key findings suspicious for recurrence were enhancement and soft tissue thickening of the NSF. These findings were present in at least one postoperative scan in all patients. Conclusion Neuroradiologists and rhinologists performing surveillance on patients with a history of skull base malignancy with NSF reconstruction should maintain collaborative efforts to accurately interpret radiologic findings of the NSF during postoperative imaging.     

A New Concept for Classifying Skull Base Defects for Reconstructive Surgery

To classify the defects of the skull base, we present a new concept that is intuitive, simple to use, and consistent with subsequent reconstructive procedures. The centers of defects are determined in the anterior (I) or middle (II) skull base. The defects are classified as localized in the defect''s center (Ia, IIa) or extended horizontally (Ib, IIb) or vertically (Ic, IIc) from the defect''s center. Accompanying defects of the orbital contents and skin are indicated by “O” and “S,” respectively. An algorithm for selecting subsequent reconstructive procedures was based on the classification. Using the new system, we retrospectively reclassified 90 skull base defects and examined how the defect classifications were related to the reconstructive flaps used and postoperative complications. All defects were reclassified with the new system without difficulty or omission. The mean correlation rate was high (88%) between the flaps indicated by the new classification and the flaps that had actually been used. The rate of postoperative complications tended to be higher with Ia, Ic, and IIb defects and combined defects. Our new classification concept can be used to classify defects and to help select flaps used for subsequent reconstructive procedures.     

Combined Transcranial-endonasal Reconstructive Surgery for Cerebrospinal Fluid Leakage Resulting from Traumatic Anterior Skull Base Fractures Involving the Parasellar Region

Extensive traumatic anterior skull base fractures from the frontal sinus to the parasellar region are frequently accompanied by multiple dural defects that cause persistent cerebrospinal fluid (CSF) leakage. Conventional transcranial reconstruction using a frontal periosteal flap is frequently insufficient, and parasellar dural defects are often deep, complex, and difficult to identify. In this report, we describe a combined transcranial–endonasal reconstructive technique and report our experience. Simultaneous combined transcranial and endoscopic surgery was performed in three patients with CSF leakage resulting from traumatic anterior skull base fractures. Dural defects were thoroughly identified from the transcranial and endonasal surgical fields, and covered using a multilayer sealing technique. The anterior regions of the anterior skull base were reconstructed using a free fascial flap and frontal periosteal flap; posterior and parasellar regions were reconstructed using a fat graft, vascularized nasoseptal flap, and endonasal balloon. Suturing the transcranial grafts to the parasellar dura mater was performed collaboratively by the transcranial and endonasal surgeons. In our cases, complete cessation of CSF leakage was achieved without perioperative lumbar drainage in all patients. Mean time to postoperative ambulation was 7 days (range, 3–11). No surgical complications occurred. Simultaneous transcranial and endonasal procedures were helpful to detect all sites of CSF leakage and secure reconstructive grafts. The combined transcranial and endonasal reconstructive technique achieved secure skull base reconstruction without recurrence of CSF leakage, and allowed early postoperative ambulation. This technique can be a reliable surgical option to repair CSF leakage resulting from extensive anterior skull base fractures.     

Reconstruction of the median anterior skull base with an intracranial free radial forearm flap after recurrent resection of tumour

Abstract

We report a case of a median anterior skull base defect that was reconstructed with a free radial forearm flap. The flap was used intracranially, whereas the vascular anastomosis was made extracranially, with the pedicle running through a burr hole in the skull. This technique was succesful in sealing the skull base from the nasal cavity and preventing leakage of cerebrospinal fluid, infection, or herniation of brain tissue. We report the reconstructive procedure, an overview of other options, and the reasons for the decisions in this case.     

The Reverse-Flow Facial Artery Buccinator Flap for Skull Base Reconstruction: Key Anatomical and Technical Considerations

Objective To highlight key anatomical and technical considerations for facial artery identification, and harvest and transposition of the facial artery buccinator (FAB) flap to facilitate its future use in anterior skull base reconstruction. Only a few studies have evaluated the reverse-flow FAB flap for skull base defects. Design Eight FAB flaps were raised in four cadaveric heads and divided into thirds; the facial artery''s course at the superior and inferior borders of the flap was measured noting in which incisional third of the flap it laid. The flap''s reach to the anterior cranial fossa, sella turcica, clival recess, and contralateral cribriform plate were studied. A clinical case and operative video are also presented. Results The facial artery had a near vertical course and stayed with the middle (⅝) or posterior third (⅜) of the flap in the inferior and superior incisions. Seven of eight flaps covered the sellar/planar regions. Only four of eight flaps covered the contralateral cribriform region. Lastly, none reached the middle third of the clivus. Conclusions The FAB flap requires an understanding of the facial artery''s course, generally seen in the middle third of the flap, and is an appropriate alternative for sellar/planar and ipsilateral cribriform defects.     

Review of skull base reconstruction using locoregional flaps and free flaps in children and adolescents

Tumors of the skull base are rare in children, and reconstruction in such patients has rarely been reported. We reviewed 16 cases of skull base reconstruction in patients under 18 years. The study group consisted of 10 boys and 6 girls, whose ages ranged from 2 to 17 years. Of the 16 cases, eight tumors were benign and eight were malignant. Defects were anterior in six cases, lateral in eight cases, and anterolateral in two cases. Reconstruction was performed with locoregional flaps in 11 cases and with free flaps in 5 cases. No significant difference was found between locoregional flaps and free flaps in total operative time, intraoperative blood loss, or postoperative hospital stay. However, in some cases, total operative time, reconstruction time, and blood loss increased to a degree unacceptable for pediatrics. Minor complications occurred in three patients and a major complication occurred in one case. Of four patients, three patients with postoperative complications had undergone chemoradiotherapy. Because of the physical weakness of pediatric patients, complicated reconstructive procedure should be avoided. We believe locoregional flaps will become the first choice for reconstruction. However, if patients have large, complex defects and have received radiotherapy, appropriate free flaps should be used to avoid postoperative complications.     

Outcomes following Microvascular Free Tissue Transfer in Reconstructing Skull Base Defects

Objective Successful resection of complex tumors involving the skull base (SB) depends on the ability to reconstruct the resulting defects. The objective of this study was to assess the outcomes of patients undergoing reconstruction after resection of SB tumors with free flaps.Methods From 1995 to 2010 a retrospective review of cases was undertaken. Demographics, histology, surgical management, complications, locoregional control, and survival were analyzed.Results We performed 62 flaps in 57 patients. There was a preponderance of sinonasal malignancies (45%), and most lesions involved the anterior SB (81%). A total of 94% of patients underwent radiotherapy. Reconstruction was undertaken mainly with anterolateral thigh (37%) or radial forearm (34%) flaps. Complications occurred in 17% of patients, and the flap''s success rate was 94%.Conclusion Free flaps are versatile and highly reliable for reconstructing defects resulting from resections of the SB. They should be considered for SB reconstruction of large three-dimensional defects as well as defects involving an irradiated field. Successful reconstruction of the SB can be performed using a small number of highly dependable flaps.     

Reconstruction of an extensive anterior skull base defect using a muscle‐sparing rectus abdominis myocutaneous flap in a 1‐year‐old infant

Despite the recent advances in microsurgical techniques, reconstruction of extensive skull base defects using free flaps in pediatric patients presents a surgical challenge, and reports on skull base reconstruction in infants is quite limited. We present a case of reconstruction of an extensive anterior skull base defect using a rectus abdominis (RA) myocutaneous flap in a 1 year‐old (14 months) infant. Sufficient coverage of the intracranial contents, good aesthetic results, and minimal growth disturbance at the donor site were achieved by the muscle‐sparing RA flap transfer. To the best of our knowledge, this was among the youngest case of skull base reconstruction using a free flap. The feasibility of free flap transfer and flap selection in pediatric skull base reconstruction is discussed. © 2012 Wiley Periodicals, Inc.     

Osteocutaneous radial forearm free flap for anterior cranial base reconstruction: Technical note

The reconstruction of anterior skull base defects after carcinologic surgery is challenging. Large defects can require the use of autologous free tissue transfer. Currently, most reconstructions use soft-tissue flaps. We describe the use of an osteocutaneous radial forearm free flap to reconstruct a large defect secondary to a malignant paraganglioma extending into the anterior cranial fossa and both orbits. The surgical resection required endonasal and transcranial approaches. We reconstructed the defect with a free osteocutaneous radial forearm flap. We laid the bone flap across the defect, resting on the orbital roof on each side, and sutured the soft component to the edge of the dura. The pedicle was funnelled from the craniotomy to a prepared cervicotomy and the micro-anastomoses were performed onto the facial artery and two satellite veins. Potential indications and major drawbacks of this technique are briefly discussed. Osteocutaneous radial forearm free flaps can be a valuable reconstructive option for patients with a large defect of the anterior skull base, needing both rigid support and a watertight closure.     

Surgical treatment of anterior skull base tumours

Summary Skull base tumours represent a special challenge to surgeons due to the complex anatomy of the area. While small tumours are easy to remove, large lesions can pose complex situations. The most difficult aspects are not only the approach and removal, but specially the repair of the defects created by the resection of the tumour.We present here our experience with the surgical removal of tumours on the anterior skull base. To achieve a good approach, we resort to a bifrontal craniotomy including the cilliar arches. To obtain a skull base bone flap that can be used for repair at the end of the procedure, we remove the roof of the nose and a part of the medial wall and roof of both orbits. While the tumour is removed, the skull base bone flap is autoclaved to kill all tumoural cells. At the end of the procedure this bone flap is replaced, wrapped with a flap of pericranium. Provided no orbit needs to be emptied, no other flap is needed to reconstruct the area. One advantage is that the surgical cavity is not occluded with tissues, thus facilitating early identification of any recurrence. The area can be explored with the aid of an endoscope introduced into the nasal cavities through the nostrils, and in case of doubt, biopsies taken from all suspicious areas.Our technique facilitates the repair of the surgical defect, and while not compromising the healing process it has a very low incidence of CSF leaks and infections.     

游离皮瓣在颅骨外露的头皮缺损中的应用

目的:报告应用游离皮瓣修复头皮缺损致颅骨外露的方法和临床疗效。方法:本组5例患者年龄5～58岁,平均35岁,因创伤、肿瘤等原因造成头皮部分缺损并颅骨外露,缺损面积在8cm×10cm～15cm×10cm;缺损部位为颞部、顶部及额部。分别选用游离胸脐皮瓣、旋股外侧皮瓣和胫后动脉皮瓣等移植修复创面。结果:本组5例患者移植皮瓣Ⅰ期成活,其中2例移植皮瓣后行头皮扩张术,术后扩张头皮全部覆盖创面,毛发生长良好。术后随访6～18个月,患者皮瓣除臃肿外,创面Ⅰ期愈合,外形效果好。结论:采用吻合血管的游离皮瓣移植修复颅骨缺损,可以在短期内完全覆盖裸露的颅骨,确保了颅骨的成活。皮瓣成活后,可以Ⅱ期手术修整或头皮扩张术,既修复创面又能恢复头部外观,是一种理想的修复方式。     

Reconstruction of Lateral Skull Base Defects with Radial Forearm Free Flaps: The Double-Layer Technique

Introduction The radial forearm flap has fallen out of favor in lateral skull base reconstruction in recent literature. However, especially when used in a double layer, a radial forearm may be able to provide the thickness of a large flap while taking advantage of the pliability for which the flap is renowned. Objective To report the results of the double-layer technique of radial forearm free flap reconstruction of lateral temporal bone defects. Design A retrospective chart review. Setting A tertiary care institution. Participants All consecutive patients who underwent lateral temporal bone resections and were reconstructed with free flaps from 2006 to 2012. Major Outcome Measures Flap success rate, complications, and rate of revision surgery. Results A total of 17 patients were identified with free flap reconstruction of the lateral skull base. Seven received reconstruction with a double-layer radial forearm flap. Reconstruction-related complications in this group included one case of facial cellulitis. The flap success rate was 100%. These results were comparable with patients who had other flaps. Conclusions The radial forearm free flap may be an effective reconstruction option for lateral temporal bone defects especially when used in the double-layer technique.     

Free tissue transfer and local flap complications in anterior and anterolateral skull base surgery

BACKGROUND: Advances in reconstructive techniques over the past two decades have allowed the resection of more extensive skull base tumors than had previously been possible. Despite this progress, complications related to these cases remain a concern. METHODS: Univariate and multivariate analyses were used to determine the relationship of host, tumor, defect, treatment, and reconstructive variables to wound and systemic complications after anterior and anterolateral skull base resections. The study included 67 patients receiving local flap (LF) or free tissue transfer (FTT) reconstructions during an 8-year period. RESULTS: Overall, 28% of patients had a major wound complication, and 19% had a major systemic complication. LF and FTT flaps had similar rates of wound complications. LF reconstructions were associated with late wound breakdown problems, and FTT flap complications were primarily acute surgery-related problems. CONCLUSIONS: The surgical reconstruction of skull base defects should be planned on the basis of the ability of the technique to attain safe closure and maintain integrity after radiation therapy.     

Extended Inferior Turbinate Flap for Endoscopic Reconstruction of Skull Base Defects

Objective When the use of the nasoseptal flap for endoscopic skull base reconstruction has been precluded, the posterior pedicle inferior turbinate flap is a viable option for small midclival defects. Limitations of the inferior turbinate flap include its small surface area and limited arc of rotation. We describe a novel extended inferior turbinate flap that expands the reconstructive applications of this flap. Design Cadaveric anatomical study. Participants Cadaveric specimens. Main Outcome Measures Flap size, arc of rotation, and reconstructive applications were assessed. Results The average width of the flap was 5.46 ± 0.58 cm (7.32 ± 0.59 cm with septal mucosa). The average length of the flap was 5.01 ± 0.58 cm (5.28 ± 0.37 cm with septal mucosa). The average surface area of the flap was ∼ 27.26 ± 3.65 cm² (40.53 ± 6.45 cm² with septal mucosa). The extended inferior turbinate flap was sufficient to cover clival defects extending between the paraclival internal carotid arteries. The use of the flap in 22 cadavers and 5 clinical patients is described. Conclusion The extended inferior turbinate flap presents an additional option for reconstruction of skull base defects when the nasoseptal flap is unavailable.     

A Reconstruction Method Using Musculopericranial Flaps that Prevents Cerebrospinal Fluid Rhinorrhea and Intracranial Complications after Extended Anterior Skull Base Resection

Anterior skull base defects after extended anterior skull base resection including unilateral orbit and the dura were reconstructed using the temporal musculopericranial (TMP) flaps or frontal musculopericranial (FMP) flap in 14 patients. Dural defect was reconstructed with the TMP or FMP flap by making it overlap on the remaining dura around the defects. These flaps were also used, in principle, for the separation of the nasal cavity. For bone defects on the anterior skull base, a bone graft was transplanted in the place between the flap for dural reconstruction and the flap for the separation of the nasal cavity. Bone grafting was nor performed in patients who had an extensive defect and for whom a free flap was used for the separation. After surgery, CSF rhinorrhea did not occur in the 14 patients. Twelve patients did not develop any postoperative complications. Two patients had epidural abscess, but with debridement and the drainage to the nasal cavity, they did not develop severe intracranial complications. We conclude that reconstruction using musculopericranial flaps is a reliable and versatile method with minimum invasion and the shortest operation hours. In particular, musculopericranial flap for dura reconstruction was highly efficacious for the prevention of CSF rhinorrhea.     

A Reconstruction Method Using Musculopericranial Flaps that Prevents Cerebrospinal Fluid Rhinorrhea and Intracranial Complications after Extended Anterior Skull Base Resection

Anterior skull base defects after extended anterior skull base resection including unilateral orbit and the dura were reconstructed using the temporal musculopericranial (TMP) flaps or frontal musculopericranial (FMP) flap in 14 patients. Dural defect was reconstructed with the TMP or FMP flap by making it overlap on the remaining dura around the defects. These flaps were also used, in principle, for the separation of the nasal cavity. For bone defects on the anterior skull base, a bone graft was transplanted in the place between the flap for dural reconstruction and the flap for the separation of the nasal cavity. Bone grafting was nor performed in patients who had an extensive defect and for whom a free flap was used for the separation. After surgery, CSF rhinorrhea did not occur in the 14 patients. Twelve patients did not develop any postoperative complications. Two patients had epidural abscess, but with debridement and the drainage to the nasal cavity, they did not develop severe intracranial complications. We conclude that reconstruction using musculopericranial flaps is a reliable and versatile method with minimum invasion and the shortest operation hours. In particular, musculopericranial flap for dura reconstruction was highly efficacious for the prevention of CSF rhinorrhea.     

Combined use of a radial fore arm free flap for extra-intracranial bypass and for antero-lateral skull base reconstruction – a new technique and review of literature

Summary This article describes a new surgical technique consisting of the combined use of a fascial radial fore arm free flap (RFFF) as vascular graft for extra-intracranial bypass and as dura mater plasty for reconstruction of the antero-lateral skull base. This new technique is illustrated by a case of a complex intracranial meningioma with extracranial extension necessitating resection of internal carotid artery. The technical issues of antero-lateral skull base reconstruction and extra-intracranial bypass are discussed and the literature is reviewed.     

Use of anterolateral thigh and lateral arm fasciocutaneous free flaps in lateral skull base reconstruction

Lateral skull base defects following tumor ablation are ideally reconstructed with microvascular free tissue transfer. Although the rectus abdominis free flap is the workhorse in skull base reconstruction, it has a number of drawbacks. Anecdotal reports have indicated that fasciocutaneous free flaps may be useful alternatives in selected cases. Patients undergoing lateral arm (4 cases) or anterolateral thigh (8 cases) fasciocutaneous free flap reconstruction of lateral skull base defects between 1999 and 2005 were therefore reviewed. Twelve consecutive patients (4 males, 8 females) with a mean age of 63 years (range, 39 to 74) underwent such reconstruction following resection of lateral (11 cases) and anterolateral (1 case) skull base lesions. Eight patients had squamous cell carcinoma, 3 had infection or osteoradionecrosis, and 1 had adenoid cystic carcinoma. The duration of surgery (from induction of anesthesia to exit from the operating room) averaged 14.5 hours (range, 10 to 19.5 hours). All donor sites were closed directly. All the flap transfers were successful, with minimal reconstructive and donor site morbidity. During the follow-up period (average, 18 months; range, 2-48 months), 2 patients died of metastatic disease, and another 2 died of other unrelated causes. The remaining 8 patients are alive and disease free. It is concluded that lateral arm and anterolateral thigh fasciocutaneous free flaps should be considered as viable reconstructive options for lateral skull base ablative defects.     

游离肋骨-前锯肌-皮肤复合组织瓣修复大面积颅骨缺损

目的:探讨吻合血管的游离肋骨-前锯肌-皮肤复合组织瓣修复大面积颅骨缺损的临床应用价值。方法:设计以胸背血管为营养血供的游离肋骨-前锯肌-皮肤复合组织瓣,用以修复大面积颅骨缺损10例。结果:10例患者,组织瓣完全成活9例,坏死1例。随访1～10年,患者术后外观满意,无感染、皮下积液等并发症发生。结论:游离肋骨-前锯肌-皮肤复合组织瓣可以很好地完成大面积颅骨缺损的修复,是一种理想的自体修复材料。