Union and bone resorption of free fibular flaps in mandibular reconstruction.

BACKGROUND: The purpose of this study was to evaluate bony union and resorption after free fibular flap reconstruction for mandibular reconstruction. METHODS: A total of 112 patients with composite resection and reconstruction with a fibular free flap were included. Computed tomography scan images taken after the reconstruction and approximately 1 year postoperatively were assessed to evaluate union (n = 60) and bone resorption (n = 24) of the neomandible. RESULTS: Most of the fibulas healed well (n = 34) and there was radiologic nonunion in 20% of the neomandibles at the time of evaluation (mean = 15 months). There was a statistically significant reduction in bone height in the native mandible (p = 0.02) and the anterior part of the fibular graft (p = 0.02). CONCLUSIONS: There was a statistically significant reduction in mandibular and fibular graft height. However, the bone resorption was clinically minimal. Sufficient maintenance of height and good bony union support the use of free fibular flap in mandibular reconstruction.

Second free flaps in head and neck reconstruction.

INTRODUCTION: Ablative surgery for head and neck cancer often results in defects that require free flap reconstruction. Improved survival after refined oncologic and adjuvant techniques has led to an increase in the number of patients undergoing a second free flap reconstruction. The objective of this study was to assess outcomes following a second free flap in head and neck reconstruction. MATERIALS AND METHODS: Following ablative defects in the head and neck, 1475 patients underwent reconstructive surgery over a period of 17 years. A second free flap for reconstruction was performed on 123 of these patients. In Group 1, 93 patients had a reconstruction for either tumour recurrence, second primary tumour or reconstructive complications (fractured plate, osteoradionecrosis, orocutaneous fistula). In Group 2, 30 patients had a second free flap following primary free flap reconstructive failure. RESULTS: Flap success for Group 1 patients was 86/90 (96%) compared to group 2 patients, 22/30 (73%) (p < 0.05). In Group 1, partial necrosis occurred in four patients whereas in Group 2, there was only one partial necrosis (NS; p > 0.05). CONCLUSION: A second free flap may be required for reconstruction of head and neck defects following complications of the initial reconstruction, presence of a second primary or tumour recurrence. Success rates for second free flap reconstructions were significantly lower in those patients with initial free flap failure.

Vascular endothelial growth factor and its receptors are expressed in human nerve grafts.

Vascularization and angiogenicity of human nonvascularized nerve grafts in the second stage of facial reanimation were studied. Immunohistochemistry for endothelial markers (CD-31) and vascular endothelial growth factor (VEGF) and its receptors Flt-1 and Flk-1 was performed on distal end biopsies from 35 cross-facial nerve grafts. In grafted nonvascularized nerve, density of vascular structures (also clearly immunopositive for VEGF and both receptors) showed a mean of 166 vessels (range 78 to 267) per unit area, corresponding to control values. In addition, VEGF was expressed in axons and perineural structures. In control samples, VEGF expression was low and occurred in the myelin sheath. In nerve grafts, expression of Flt-1 and Flk-1 (less intense) was seen in axons and perineural structures. A higher density of vessels was associated with lower VEGF expression (not significant). In short, expression of VEGF and its receptors is described in human nerve grafts and compared with basic histology and p75 nerve growth factor receptor expression of the nerve graft and functional outcome of patients.

P75 nerve growth factor receptor is expressed in regenerating human nerve grafts.

BACKGROUND: The purpose of this study was to elucidate the expression of p75 nerve growth factor receptor (p75NGFR) in human cross-facial nerve grafts and to compare the immunohistological findings with patient data and the functional outcome in facial reanimation. MATERIALS AND METHODS: The study comprised 37 sural nerve graft specimens. All of the patients had long-lasting complete facial paralysis and were operated on by the standard two-stage procedure involving cross-facial nerve grafts and microneurovascular muscle transfer. Nerve biopsies were taken 4 to 20 months (mean, 8 months) after the cross-facial nerve grafting. Immunohistochemistry for p75NGFR as well as for Schwann cells (S-100; Dako, Glostrup, Denmark) and for Neurofilament-200 (NF-200; Boehringer, Mannheim, Germany) was performed. RESULTS: In graft biopsies, the mean number of NF-200-positive axons amounted to 38% (range, 6-81%) of that in control samples. Further, regenerated axons were thinner than in control samples. Morphologically, the grafted nerves were characterized by fibrosis and invasion of inflammatory cells. A longer time between cross-facial nerve grafting and biopsy sampling correlated with a higher number of viable axons (NF-200) (P = 0.002). In all cases, expression of p75NGF receptor was clearly higher at the distal end of the grafted nerve. Expression of p75NGFR was lower in older than in younger patients (P = 0.003). A high expression of p75NGFR was often seen with better function of the transplanted muscle. CONCLUSION: Increased expression of p75NGFR in human nerve grafts was noted, especially in younger patients. We suggest that p75NGFR expression might be a contributing factor in a successful axonal regeneration and eventual recovery of muscle function.

Long-term adaptation of human microneurovascular muscle flaps to the paralyzed face: an immunohistochemical study.

The purpose of this study was to characterize microneurovascular (MNV) muscle transplants immunohistochemically up to 10 years after transfer. Histological data was related to long-term functional outcome. The study comprised 17 patients with a mean age of 41 years suffering from complete unilateral long-lasting facial paralysis. A two-stage procedure was performed between 1986 and 2001. The gracilis, latissimus dorsi, and serratus muscles were used in four, eight, and five patients, respectively. Eighteen biopsy samples were taken from MNV muscle grafts during secondary refinement procedures. In one patient, the tissue samples were collected at two different time points. Immunohistochemistry testing revealed muscle fiber type distribution (anti-myosin fast), proliferating satellite cells (Ki-67), and reinnervation (S-100). Muscle atrophy was assessed histomorphometrically. In a recent study, patient characteristics and the function of the flap were evaluated. Histological data were compared with clinical data and long-term functional outcomes of the patients. In biopsy samples taken 1-10 (mean 31 months) years after MNV muscle transfer, the mean muscle fiber diameter was 38 (range 14-70) microm, indicating a 40% decrease compared with control values. Muscle atrophy was not type-specific and the mean percentage of type II fibers was not altered. Individual variation was, however, considerable. Proliferative activity of satellite cells was seen in 60% of the samples but it tended to decline with an increase in follow-up time. All samples showed intramuscular reinnervation. In statistical analysis severe atrophy correlated with prolonged intraoperative ischemia (P=0.04). The good long-term functional outcome correlated with dominance of fast fibers in muscle grafts (P=0.03). Atrophy tended to be more pronounced in the serratus than in the other muscles (ns). In summary, despite dense muscle reinnervation, morphology of the muscle is not fully restored after muscle transfer. Ischemia time affects muscle morphology. Adaptation of the graft to fast-twitch muscle activity favors better mimic function. The proliferative activity of satellite cells declines with prolonged follow-up time.

Facial reanimation by transplantation of a microneurovascular muscle: long-term follow-up.

The two-stage operation for reanimation of long-standing facial paralysis by cross-facial nerve grafting and later free microneurovascular muscle transfer has been the treatment of choice for nearly 25 years. However, the functional outcome may be unpredictable. We therefore need to know more about the factors that influence the final result. We have recorded the long-term results of microneurovascular surgery in facial paralysis, and evaluated which factors influenced the functional outcome. Twenty-seven of 40 patients aged 7 to 65 years (mean 40) operated on at Helsinki University Hospital between 1986 and 2000 were available for interview and video recording. The gracilis, latissimus dorsi, and serratus anterior muscles were used for microneurovascular transfer in 11, 10, and 6 cases, respectively. The outcome of microneurovascular muscle transfer was graded on House's scale 1 to 6. The mean follow-up period was 8.5 years (range 2 to 15). Sixteen patients (59%) displayed only mild or moderate dysfunction (grades 2 to 3) after reconstruction. In 8 patients (30%) dysfunction was graded as moderately severe, and in 3 (11%) as severe. There was a correlation between final functional outcome and the follow-up time after microneurovascular facial reanimation. The longer the follow-up time after muscle transplantation the poorer the functional result (p = 0.003). Twenty-one patients (78%) considered that their quality of life was better or much better after facial reanimation. Patients' satisfaction correlated with a good functional result.