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Rigid Postoperative Fixation for Pedicled Cranial Flaps: A Case Comparison

Aaron J. Noordmans, BS
Nicole Parent, CO
Vikas Bhatia, MS
Mary E. Garrity-Moses, BS
Nicholas M. Boulis, MD

ABSTRACT Reconstruction after head and neck surgery in congenitally malformed, irradiated, or traumatized tissue may preclude the use of free-flap techniques. In these cases, pedicled flaps provide a useful alternative. Development of methods designed to ensure adequate perfusion of these flaps is essential to their survival. The present report compares two cases in which pedicled arm flaps were employed in face and head reconstruction. In the first case, incomplete immobilization allowed for flap failure, whereas complete immobilization in the second case improved patient comfort, supported persistent flow in the pedicle, and resulted in a viable flap. Follow-up examination at 1 year in the second case revealed healthy, well-vascularized tissue at the surgical site. Survival of pedicled arm to head flaps for cranial reconstruction benefits from three-way immobilization securing head to torso, torso to arm, and arm to head.

Keywords: Pedicled cranial flap, orthosis, halo, cranial reconstruction, basal cell carcinoma.

Unlike free tissue flaps, pedicled flaps must remain immobilized to mature properly.¹ Although the techniques of flap surgery are well described, options for the postoperative immobilization necessary for successful flap maturation remain limited. Pedicled flaps remain a useful method to bring well-vascularized tissue to hypovascular donor sites as may exist in cases of congenitally malformed, irradiated, or traumatized tissue. Successful application of radial forearm pedicle flaps to the head depends both on adequate blood flow to and away from the pedicle and on optimal length/width ratio of the flap.² Persistent flap survival relies on the maintenance of adequate perfusion after tissue transfer. The maintenance of flow depends, in turn, on the immobilization of the flap in relation to the transfer site. Several methods have been employed to achieve immobilization, including casts and devices, such as the Hoffmann apparatus, designed to affect this end.³ The present report compares two cases in which arm-pedicled flaps were attached to the head and preoperatively designed orthoses were applied for immobilization to ensure flap survival. In the first case, incomplete immobilization allowed for flap failure, whereas complete immobilization in the second case improved patient comfort, supported persistent flow in the pedicle, and resulted in a viable flap. This is the first report to our knowledge of a device designed for complete immobilization of a radial arm pedicle flap to the head.

METHODS

CASE 1: UPPER LIP RECONSTRUCTION VIA UPPER LATERAL FOREARM PEDICLED FLAP

A 30-year-old man suffered from a self-inflicted gunshot wound to the mid-face, mandible, and nasal ethmoid complex. He underwent three failed attempts at free tissue reconstruction within 2 years. In anticipation of a pedicled flap, an orthosis designed for patient comfort and limited motion between the arm and head was designed. Preoperative evaluation revealed optimal arm position to involve 140° of shoulder flexion, maximal horizontal adduction, and 120° of elbow flexion, eliminating strain on the flap pedicle. Measurements for modifications to a prefabricated shoulder abduction orthosis were taken preoperatively. The thoracic component was rigidly attached to the humeral component with an adjustable position joint to allow minute adjustments to be made postoperatively. The thoracic component included a half-circumferential thoracic and pelvic band providing a left medially directed force opposed by lateral chest straps, which created right medially directed force. This resultant full circumferential force provided a stable base of support from which to direct the position of the arm. To maintain the arm in flexion, a proximally acting axial force was applied to the humerus. The rigid humeral-elbow-forearm section of the orthosis provided a superiorly directed force to block shoulder extension. The elbow joint of the orthosis was locked at 120° of flexion and Velcro straps pulling the elbow toward flexion blocked elbow extension and strain on the graft. This orthosis accomplished complete immobilization of the arm with respect to the torso in the optimal position for graft survival. In this design, head position was dependent on the natural position of the neck. Resting position of cervical flexion and slight anterior translation with postural kyphosis provided a resting, natural posteriorly directed force to oppose the superiorly directed force of the humeral component, maintaining contact between the lip and the forearm.

Staged direct transfer of a 5- × 6-cm local skin flap from the left upper forearm to the left lip was conducted. An area on the patient's forearm was carefully measured and a 5- × 5-cm rectangular flap was cut, leaving a 5 cm base attached to the distal upper forearm. The flap was then tubed, leaving an area superiorly to granulate, so that a band would form to assist with the palatal prosthesis. Once tubed, the arm was brought to the region of the head and neck and turned approximately 110 degrees to be sewn into position at the left lateral upper lip. Care was taken not to agitate the extensor fascia.

The orthosis was applied in the operating room in the supine position. It seemed to support the arm in the desired position and only slight adjustments were made for comfort before the patient was discharged. Three days later it was determined that the patient was having difficulty tolerating the position because of his tendency to turn his head to the right. Head and neck motion was not rigidly fixed in the orthosis. Despite attempts to use analgesics and sedation to minimize strain on the graft, persistent cervical motion was observed to compromise the integrity and vascularity of the flap. Therefore, a two-piece rigid split system strap was added to the forearm section of the orthosis. One strap was attached anteriorly to the humeral section and one strap was attached posteriorly to the posterior thoracic band. A molded head pad was added to the inside of the posterior strap to block right lateral flexion and rotation of the neck. The straps, although secure, could be removed by the patient. This provided limits to the motion of the head and neck but failed to provide complete immobilization. In conjunction with a self-administered overdose of narcotics 2 days later, the patient forcefully detached the graft from his face.

CASE 2: PEDICLED LEFT RADIAL FOREARM FLAP TO SCALP

An 86-year-old man was diagnosed with a squamous cell carcinoma eroding into the calvarium at the junction of the forehead and frontal scalp directly over the sagittal sinus. Approximately 1 year before the present case, the patient had an initial tumor resection, multiple local flaps, and frontal and temporal scalp radiation. Despite this treatment, the tumor recurred locally. Reoperation required a wide lateral excision of the squamous cell carcinoma, intraosseous tumor, and craniectomy. Because of lack of adequate vessels for microvascular anastomosis and revascularization of a free flap, a pedicled radial forearm flap was planned.

The optimal arm position for flap survival was determined preoperatively to involve 160° of shoulder abduction, maximal shoulder internal rotation, 120° of elbow flexion, forearm pronation, and wrist flexion. A modified halo orthosis was designed to passively position the arm in relation to the head, eliminating the need for muscle activity and completely immobilizing the patient's arm with respect to his head (Figure 1 ). The orthosis was designed to provide external support, maintain contact to the scalp, and prevent strain on the flap.

The patient's passive range of motion was adequate to maintain the position specified; however, rigid fixation of the arm to the torso was required to decrease migration of the arm in an upright position. A negative plaster mold was taken of the arm and torso separately. The arm was placed in contact with the designated superior aspect of the head, in optimal position. The two negative molds were connected with plaster splints to reflect the relationship between the torso and arm in this position. Thermoplastic (Spartech, Missouri) was pulled to form a modified bivalve torso shell rigidly connected to a dorsal shoulder-elbow-wrist-hand orthosis (SEWHO) (Figure 1D ). The SEWHO portion of the orthosis incorporated trimlines to provide a posterior-directed force to prevent elbow extension and forearm supination. A locking, telescoping aluminum bar connecting the torso section and the SEWHO section (Figure 1F ) provided a superior-directed force to prevent shoulder adduction. This aluminum bar was attached to a modified halo vest. The lateral standard plastic chest strap on the halo vest was replaced with a channeled aluminum strut connected to the telescoping bar (Figure 1G ). This provided a rigid platform to support the superior-directed force, maintaining shoulder abduction ( Figure 1G ). The below-the-elbow section of the SEWHO allowed free exposure of the volar aspect of the forearm so as not to impinge on the flap and allow access to test vascularity without removal of the orthosis. A two-section elastic strapping system placed distal to the elbow and proximal to the wrist provided additional-superior directed force and prevented excess elbow flexion beyond 120° and subsequent pressure from the weight of the arm on the flap (not shown in Figure 1). The dorsal shell SEWHO was rigidly attached to the halo distally (Figure 1A ) and proximally (Figure 1E ) with adjustable positioned aluminum connections.

Tumor excision resulted in a defect measuring 14 × 10 cm. The calvarium underneath the tumor site was removed without entering or resecting the dura or underlying sagittal sinus. A skin paddle used to match the surgical defect in the scalp centered over the radial artery was dissected fully and circumferentially in the subfascial plane of the proximal forearm. The flap was left pedicled through its vascular attachments to the forearm. All branches of the superficial radial nerve were preserved. A skin graft from the left thigh was then applied where the skin paddle had been harvested. The 14- × 10-cm graft, 0.4 mm thick, was sewn into the scalp defect. Care was taken not to constrict the vascular pedicle.

Postoperatively, an adjustable circumference halo ring (DePuy AcroMed Inc., Raynham, MA) with anterior and posterior halves, compatible with placement around the head despite the attached pedicle, was joined to form a solid ring (Figure 1B ). Six skull pins, two anterior and four posterior, set at 8 inch-lbs, were used to secure the ring. Care was taken to position the halo vest at the level of the costal margin to prevent superior-directed pressure during sitting. The cervical spine was immobilized in a position of slight lateral flexion toward the affected arm in the coronal plane, and neutral flexion/extension in the sagittal plane (Figure 2 ).

Doppler testing of pedicle perfusion in the upright position revealed significantly decreased flow. The two aluminum connections were recontoured to provide additional distraction force and decrease the weight of the arm on the flap. Doppler pulse improved. Over the course of the 8-week immobilization, the patient remained hospitalized. Minimal adjustments to the orthosis were needed for comfort. The patient was able to sit up and ambulate comfortably on a limited basis.

After 8 weeks of immobilization, the patient underwent flap takedown and the orthosis was removed. The patient's independently viable flap was well perfused with adequate color and warmth. He was placed in a soft cervical collar and shoulder abduction sling. The patient experienced decreased sensation and mobility of the hand and arm as well as significant muscle atrophy related to a minor brachial plexus injury. A nearly complete return of function occurred after 1 month of physical therapy.

DISCUSSION

Widespread application of free tissue flaps has not entirely eliminated the need for pedicled flaps. The two cases described in the present report illustrate the challenge of caring for these patients during the period in which the graft becomes independent of its pedicle. To prevent graft ischemia, torsion and stretch on the pedicle must be prevented. Additionally, prolonged limb immobilization places both physical and psychological stress on the patient. In both cases, rigid immobilization is critical to ensuring patient compliance and flap survival.

The rigid fixation of the upper extremity with respect to the head presents a unique challenge. Range of motion for both the upper extremity and the head with respect to the torso includes translation along three vectors and three separate forms of rotation. We find that the dual goals of supporting and rigidly immobilizing the limb and the head require a three-way fixation strategy. First, prevention of cervical flexion, extension, and rotation was accomplished in case 2 via halo fixation to a torso vest. Second, elbow joint flexion and extension were eliminated with the use of the molded long arm splint. Third, the shoulder joint, which allows several degrees of freedom, was immobilized with respect to all planes of motion, eliminating free abduction/adduction, flexion/extension, and medial/lateral rotation by rigidly attaching the plastic arm splint to both the halo vest and halo ring. This strategy prevents movement of the head with respect to the torso, movement of the arm with respect to the torso, and movement of the head with respect to the arm. Strategies that focus only on immobilization of the head with respect to the arm, fail to provide support, and must resist the constant stress of head and arm mobility. The fixation technique applied in case 1 failed to protect the pedicled cranial flap for this reason. Although it provided rigid fixation of the arm with respect to the torso, and splinting of the arm to prevent mobility at the elbow and shoulder, it failed to immobilize the head with respect to the torso, providing only elastic (strap) fixation of the arm to the head. This failure resulting from the absence of halo head fixation permitted pedicle compromise.

Apart from preventing torsion and stress on the flap pedicle, the treatment strategy presented in case 2 reinforced patient compliance. Rigid fixation provided increased patient comfort. In addition, this patient was kept under observation as an inpatient. The failure of compliance in case 1 was caused in part by the absence of both inpatient monitoring and rigid fixation. Case 1 also illustrates the importance of preoperative behavioral screening. In cases in which pedicled flaps are necessary in patients known to be at risk for poor compliance, the dual application of rigid fixation and close monitoring is essential.

Rigid immobilization of pedicled flaps that do not involve the head has been documented using the Hoffmann transfixation method originally designed for fracture fixation.⁴ The Hoffmann apparatus has been used primarily for cross-leg pedicle flaps. Nappi et al.⁵ point out that external fixators rigidly connecting the extremities or the extremity and torso allow for comfort, ease of flap observation, improved wound care, and ease of readjustment for relief of pedicle torque and strain. The apparatus described in the current report satisfies all of these requirements for upper extremity-to-head pedicled flaps. Disadvantages shared by the Hoffmann apparatus and the current system include the potential for joint stiffness, muscle spasm, and pin-tract infections.⁵ The substitution of rigid cross linkage with a ball-joint adapter allowing for limited motion has been applied in an attempt to prevent stiffness and spasm in the Hoffmann apparatus.⁵ In the current case, prolonged application necessary for graft maturation resulted in a minor brachial plexus injury. The future inclusion of ball joints capable of allowing temporary mobilization of the arm under supervision might prevent similar complications.

CONCLUSION

Two methods of forearm to head pedicle flap immobilization are presented. The methods differ in the techniques for movement restrictions based on the particular design of each orthosis. Complete long-term rigid immobilization with a modified halo device eliminated all degrees of freedom and insured flap survival while maintaining patient comfort and compliance.

AARON J. NOORDMANS, BS, is affiliated with the University of Southern California School of Dentistry, Los Angeles, CA.

NICOLE PARENT, CO, is affiliated with the Orthotics and Prosthetics Center, University of Michigan, Ann Arbor, MI.

VIKAS BHATIA, MS, is affiliated with the Department of Engineering, University of Michigan, Ann Arbor, MI.

MARY E. GARRITY-MOSES, BS, is affiliated with the Department of Neurological Surgery, The Cleveland Clinic Foundation, Cleveland, OH.

NICHOLAS M. BOULIS, MD, is affiliated with the Department of Neurological Surgery, The Cleveland Clinic Foundation, Cleveland, OH, and the Department of Neurology, University of Michigan, Ann Arbor, MI.

References:

1. Arnander C, Eriksson G, Korlof B, Nylen B. Transfixation in cross-leg procedures using Hoffmans's instruments. Report of forty-two cases. Scand J Plast Reconstr Surg 1975;9:68-73.
2. Lamberty BGH, Cormack GC. Progress in flap surgery: greater anatomical understanding and increased sophistication in application. World J Surg 1990;14:776-85.
3. Rosenfeld SR, Anzel SH. Use of the Hoffmann apparatus in myocutaneous pedicle flap. J Trauma 1981;21:1045-1047.
4. Eriksson F, Eriksson G, Nylen B. Open fractures: a new fixation method in cross-leg cases. Plast Reconstr Surg 1966;38:410-413.
5. Nappi JF, Drabyn GA. External fixation for pedicle-flap immobilization: a new method providing limited motion. Plast Reconstr Surg 1983;72:243-245.