Dura and cranial base reconstruction by external oblique fascia and rectus abdominis muscle flap

Reconstruction techniques in skull base surgery

One of the major challenges of cranial base surgery is reconstruction of basal dural defects. Ineffective reconstruction may result in potentially life-threatening complications such as cerebrospinal fluid leak, meningitis, and tension pneumocephalus. Goals of reconstructive procedures are to repair the dural defect and to separate intracranial contents from bacteria-laden secretion of the mouth, nose, and sinus. Different reconstructive techniques have been reported. Multiple factors may influence the surgical choice of reconstructive technique and its outcome. Regional pedicled flap and vascular free flaps represent the best reconstructive options because vascularized tissues promote fast and complete healing. A variety of endoscopic pedicled mucosal flaps within the nasal cavity have also been described. The different reconstruction techniques are described and discussed in terms of indications, advantages, and drawbacks.

Reconstruction of skull base and dura using rectus abdominis muscle combined with a vascularised fascial perforator flap

The goal of reconstruction of the skull base is to repair dural defects with a watertight seal and separate it from the nasopharynx and the exterior environment with well vascularised tissue. This prevents cerebro-spinal fluid leakage and secondary contamination leading to the potentially life threatening complications of meningitis or extradural abscess. Following large composite resections, traditional techniques to repair the dura involve the use of an autologous fascial graft or a pericranial flap, whilst a regional pedicled or free muscle flap is used to close the dead space defect. We describe a technique performed in two cases, whereby a single flap, the rectus abdominis muscle free flap, can be used to provide vascularised reconstruction both of the dura and the skull base. The anterior rectus sheath, islanded on a single perforator vessel, is used as a vascularised layer to reconstruct dura, whilst the supporting rectus abdominis muscle provides bulk to obliterate dead space. We show that this flap is suitable for reconstruction even in the presence of chronic infection. Advantages of a vascularised reconstruction are the rapid healing of the wound, even after radiotherapy, the delivery of systemic antibiotics to the site of the operation, and that it may allow early postoperative radiotherapy to be planned.

Indications for vascularized free rectus abdominis musculocutaneous flap in oromandibular region in terms of efficiency of anterior rectus sheath

The anterior rectus sheath, efficacious in reconstructive surgery, is used in oromandibular reconstruction with the free rectus abdominis musculocutaneous flap. This study describes reconstruction with this sheath in 20 patients: to preserve only the swallowing function in 10 patients (formation of the bulge of the reconstructed oral floor and prevention of its sinking); to preserve both swallowing and articulation in 5 patients (formation of the bulge of the reconstructed tongue and prevention of its sinking, concurrent with a money-pouch-like reconstruction of the tongue, laryngeal suspension, and neuroanastomosis); and to prevent exposure of the reconstruction plate, replacing the resected mandibular continuity in 5 patients. The purpose of reconstruction was achieved in all patients. The vascularized free rectus abdominis musculocutaneous flap with a firm anterior rectus sheath may be the first choice for these types of reconstruction.

Rotation flap of the anterior rectus abdominis sheath for hernia prevention in TRAM breast reconstruction

Prevention of hernia or bulge of the abdominal wall after TRAM breast reconstruction has been a challenge for the reconstruction surgeon. Different techniques have been described to avoid this complication. The use of anterior rectus abdominis sheath (ARAS) for the repair of various abdominal wall hernias has been well described in the literature and is the basis of the authors' technique. The authors present the use of ARAS flap in TRAM breast reconstruction. It is a simple and safe technique using autologous tissues for hernia or bulge prevention.

Reconstructive management of cranial base defects after tumor ablation

Successful reconstruction after cranial base tumor ablation is paramount in preventing potentially life-threatening complications. The purpose of this study was to evaluate experiences of cranial base reconstruction and to identify reconstructive management principles that may assist in achieving successful cranial base reconstruction. All cranial base reconstructions performed by the Department of Plastic Surgery at the University of Texas M. D. Anderson Cancer Center between January of 1993 and September of 1999 were reviewed. Analyses were performed to assess the impact of location of defect, type of reconstruction, type of dural repair, and history of preoperative radiation and chemotherapy on rates of complications, and patient survival. The 77 patients who underwent cranial base reconstruction after tumor ablation during the study period had a mean age of 52 years (6 to 84 years). The mean follow-up period was 28.7 months (1 to 76 months). Squamous cell carcinoma, the most common histopathologic type, was present in 24 patients (31 percent), and 35 patients (45 percent) presented with recurrent disease. Location of defects involved region I (anterior) in 31 patients (40 percent), region II (anterior-lateral) in 18 (23 percent), region III (lateral-posterior) in six (8 percent), and more than one region in 22 (29 percent). Reconstructive methods included free flaps in 52 patients (68 percent), temporalis muscle flaps in 14 (18 percent), pericranial flaps in eight (10 percent), and other local flaps (two galeal, one scalp) in three (4 percent). Of the 52 free flaps, 18 (35 percent) were used in region I, 14 (27 percent) in region II, six (12 percent) in region III, and 14 (27 percent) in defects involving more than one region. Of the 14 temporalis muscle flaps, 13 (93 percent) were used for defects involving regions I or II and one (7 percent) was used for a defect involving region III. Of the 11 pericranial and other local flaps, nine (82 percent) were used in region I, one (9 percent) in region II, and one (9 percent) in a combination of regions II and III. Complications occurred in 21 patients (27 percent): three total flap losses (4 percent), three partial flap losses (4 percent), two cerebrospinal fluid leaks (3 percent), two cases of meningitis (3 percent), two abscesses (3 percent), five cases of delayed wound healing (6 percent), two hematomas (3 percent), one wound infection (1 percent), and one cerebrovascular accident (1 percent). Overall survival was 77 percent at 2 years and 58 percent at 4 years. The type of reconstruction, location of defect, type of dural repair, and history of preoperative radiation and chemotherapy had no significant association with the incidence of complications. Neither the type of reconstruction nor the location of defect showed a significant effect on patient survival. In this experience, local flaps, such as pericranial or temporalis muscle flaps, are good choices for reconstruction of smaller anterior or lateral cranial base defects. For defects that require larger amounts of soft tissue, free flaps are appropriate. With proper patient selection, successful cranial base reconstruction can be performed with either local or free flaps with a low incidence of complications.

Microvascular reconstruction of the skull base

Cranial base reconstruction is challenging, not only because of its technical difficulty, but also because of the potentially life-threatening complications that may arise in the case of reconstructive failure. Thus, a successful outcome following skull base tumor ablation often depends as much on the reconstruction as it does on the resection. Before the advent of free tissue transfers, cranial base surgery was often limited by our inability to repair defects adequately. Free tissue transfer has been shown to be safe and effective in skull base reconstruction, and provides an opportunity for wide surgical excision of dura and skull base structures to obtain tumor-free margins. With proper patient selection and with strict adherence to the basic principles of cranial base reconstruction, including watertight dural repair and the use of well-vascularized tissue to cover the exposed dura and obliterate the dead space, successful cranial base reconstruction can be achieved. Semin. Surg. Oncol. 19:211-217, 2000.