Free Tissue Transfer
The introduction of free tissue transfers has revolutionized reconstructive surgery purposes. This is particularly important after extensive traumas, profound infections, and tumor resections.
When locoregional flaps fail to reconstruct the skull base, the microvascular surgeon faces several reconstructive challenges.
The use of vascularized, free-tissue transfer has replaced pedicled flaps as the preferred modality for reconstructing complex anterior cranial base defects involving resection of dura, brain, or multiple major structures adjacent to local skull base, including the orbit, palate, and other structures. Complication rates for patients reconstructed with free-tissue transfer techniques is similar to those patients reconstructed by conventional techniques, despite an increase in complexity of resection in this group 1).
This technique permits endoscopic endonasal inset and placement of reliable, well-vascularized free tissue that may be utilized for complex, secondary reconstruction of the skull base 2).
Independent plastic surgery centers are not available at 11 of 35 university hospitals in Germany. The purpose of this study was to demonstrate the importance of reconstructive microsurgery at a university hospital in interdisciplinary cooperation on the basis of cases treated in one year.
In 2018, 47 patients at one site underwent 50 microvascular free flap reconstructions. The data were retrospectively screened for patients' demographics, comorbidities, perioperative and postoperative details, interdisciplinary context, hospitalization, complications, and final outcomes.
Fifty free tissue flap transfers were performed after complex traumas (23.4 %), infections (25.5 %), tumor resections (42.6 %), PAD (4.2 %) and secondary lymphoedema (4.2 %). In 76.6 % of the patients, microsurgical reconstruction was performed in interdisciplinary cooperation (trauma surgery: 19.1 %, neurosurgery: 19.1 %, thoracic surgery: 4.3 %, heart surgery: 2.1 %, vascular surgery: 2.1 %, orthopedics: 25.5 %, internal medicine: 4.3 %), with 89.2 % involving at least two different departments. Postoperatively, 43.2 % of the free flaps were treated on a non-plastic surgical ward.
Reconstructive plastic surgery is of central importance in the treatment of complex surgical defect reconstructions after tumor resections, infections or traumas. Also, plastic surgery contributes substantially to the treatment of complications occurring in other specialties. For those reasons, an independent and adequately staffed department of plastic surgery should be available at all clinics of maximum care, especially at all 35 university hospitals in Germany. As this is currently not the standard of care in Germany, changes are required 3).
Kang SY, Eskander A, Hachem RA, Ozer E, Teknos TN, Old MO, Prevedello DM, Carrau RL. Salvage skull base reconstruction in the endoscopic era: Vastus lateralis free tissue transfer. Head Neck. 2018 Apr;40(4):E45-E52. doi: 10.1002/hed.25094. Epub 2018 Feb 6. PubMed PMID: 29406605.
Successful resection of complex skull base tumors involving the skull base (SB) depends on the ability to reconstruct the resulting defects. The objective of a study of Llorente et al. was to assess the outcomes of patients undergoing reconstruction after resection of SB tumors with free flaps.
From 1995 to 2010 a retrospective review of cases was undertaken. Demographics, histology, surgical management, complications, locoregional control, and survival were analyzed.
They performed 62 flaps in 57 patients. There was a preponderance of sinonasal malignancies (45%), and most lesions involved the anterior skull base (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%.
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 4).
Case series
In the years from 1976-1991, free-tissue transfer was used in 5 of 76 or 6.6% of cases, whereas free-tissue reconstruction was used in 24 of 59 or 40% of cases in the years 1992-1999. Of those cases reconstructed with free-tissue transfer in 1976-1991, 60% (three of five) underwent a complex resection defined as involving dura, brain, or more than one major structure adjacent to skull base. Of those patients reconstructed with conventional (pericranial or pericranial/galeal) pedicled flaps in this time period, 35% (25 of 71) underwent a complex resection. From 1992-1999, 75% (18 of 24) of patients reconstructed with free-tissue transfer received a complex resection, whereas only 6% (2 of 35) of patients reconstructed by other means received a complex resection.
For those patients reconstructed by free-tissue transfer, there were no instances of flap loss. Comparison of these two time periods was notable for a similar patient composition in terms of age, histologic findings, and extent of resection. Major complication rates for patients who are reconstructed with free-tissue transfer for anterior cranial base resections (31%) are similar compared with patients who have been reconstructed with conventional pedicled flaps (35%). This was noted despite an increased extent and complexity of resection in those patients who underwent free-tissue transfer reconstruction (72%) compared with those patients reconstructed by more conventional means (26%) p <.001.
The use of vascularized, free-tissue transfer has replaced pedicled flaps as the preferred modality for reconstructing complex anterior cranial base defects involving resection of dura, brain, or multiple major structures adjacent to local skull base, including the orbit, palate, and other structures. Complication rates for patients reconstructed with free-tissue transfer techniques is similar to those patients reconstructed by conventional techniques, despite an increase in complexity of resection in this group 5).
A study included 67 patients receiving local flap (LF) or free tissue transfer (FTT) reconstructions during an 8-year period.
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.
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 6).
Case reports
Aneurysmal bone cyst within fibrous dysplasia of the anterior skull base: continued intracranial extension after endoscopic resections requiring craniofacial approach with free tissue transfer reconstruction 7).