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PubMed2002

Advantages of recurrent laryngeal nerve identification in thyroidectomy and parathyroidectomy and the importance of preoperative and postoperative laryngoscopic examination in more than 1000 nerves at risk.

OBJECTIVES/HYPOTHESIS: Recurrent laryngeal nerve palsy (RLNP) is a major obstacle in thyroid and parathyroid surgery. Therefore, methods that reduce the number of temporary and, especially, permanent recurrent laryngeal nerve palsies are of great interest. One promising way to ensure the integrity of the recurrent laryngeal nerve (RLN) is to identify the nerve always. The first question raised in the present study was whether RLN preparation reduces the number of recurrent laryngeal nerve palsies or whether it introduces additional risks. Second, from former cases we know that the absence of postoperative hoarseness does not exclude RLNP, nor does postoperative hoarseness exclusively imply RLNP. Besides, misdiagnosis is not uncommon. Therefore, preoperative and postoperative laryngoscopic examination was given attention. STUDY DESIGN: Patients were investigated 1 to 7 days before and 3 to 7 days after surgery. When an RLNP was identified, patients were followed up in a 2-week rhythm the first few times and every 6 to 8 weeks thereafter until RLNP resolved or it was considered permanent after 2 years. METHODS: We prospectively investigated 608 surgical patients with 1080 nerves at risk. Because different diseases might have different rates of postoperative RLNP, we analyzed benign thyroid disease (680 nerves at risk), thyroid malignoma (321 nerves at risk), and hyperparathyroidism (79 nerves at risk) separately. Patients undergoing primary surgery (no prior thyroid surgery) and secondary interventions (there were one or more thyroid operations before this intervention) were evaluated separately. RESULTS: We found 3.4%, 7.2%, and 2.5% of temporary recurrent laryngeal nerve palsies per nerve in the benign thyroid disease, thyroid malignoma, and hyperparathyroidism groups, respectively. The prevalence of recurrent laryngeal nerve palsies in these groups was 0.3%, 1.2%, and 0%, respectively. Conforming with other studies, the total number of recurrent laryngeal nerve palsies (temporary and permanent) was not increased compared with cases with no RLN preparation, whereas the number of permanent recurrent laryngeal nerve palsies was markedly reduced. An RLN was always identifiable. Astonishingly, the restitution of an RLNP was up to 2 years in duration; however, most restitutions occurred within the first 6 months. Thirty cases of hoarseness appeared or were intensified after surgery and were not caused by RLNP. Eleven cases of postoperative RLNP had no detectable hoarseness. CONCLUSIONS: Besides indirect laryngoscopy, videostroboscopy should be performed in all cases with no evident bilateral normal laryngeal function or normal voice. Otherwise, the incidence of false-positive or false-negative diagnosis of RLNP is likely to be increased.

Adolescent↗
PubMed1991

Intrinsic pancreatic nerves after mechanical denervation of the extrinsic pancreatic nerves in dogs.

Little is known about the influence of cutting the extrinsic pancreatic nerves on the morphology and function of the intrapancreatic nerves in dogs. For this reason, intrapancreatic nerves of mongrel dogs were studied, using electron microscopy and immunohistochemistry, after truncal vagotomy, after celiac and superior mesenteric ganglionectomy, and after a combination of both operations, i.e., removing all extrinsic nerves of the pancreas. Dogs with intact extrinsic and intrinsic pancreatic nerves served as controls. Studies were performed 1-2 weeks and up to 5 months after one or both denervation procedures. For immunohistochemical and electron microscopic studies the animals were perfused with glutaraldehyde-formaldehyde-picric acid solution and the tissue was embedded in Epon or paraffin. Both immunohistochemical and electron microscopic studies revealed that signs of degenerating intrapancreatic nerves occurred only in the early phase (up to 30 days) after operation. After 60 days, hypertrophy of pancreatic nerve fibers was observed. The most striking finding was that the integrity of the intrapancreatic ganglia and nerves was almost preserved after complete extrinsic denervation. In controls there was a strong intrapancreatic innervation with vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI), substance P (SP), and neuropeptide Y (NPY) nerves. SP and NPY-nerves significantly decreased after the different denervation procedures, but the other peptidergic nerves were not altered by truncal vagotomy, ganglionectomy, or the combination of both procedures. We conclude that the dog pancreas contains extensive intrinsic peptidergic nerves, which, with the exception of SP and NPY-nerves, are greatly independent of the integrity of the extrinsic nerves.

Animals↗
PubMed1994

Facial nerve outcome after acoustic neuroma surgery: a study from the era of cranial nerve monitoring.

The introduction of intraoperative cranial nerve monitoring in posterior fossa surgery has greatly aided the surgeon in identification and anatomic preservation of cranial nerves. As a result, the long-term function of the facial nerve continues to improve after removal of acoustic neuroma. Herein, we report our long-term (1 year or greater) facial nerve outcome in 129 patients who underwent surgical removal of their acoustic neuromas with the aid of intraoperative neurophysiologic monitoring between 1986 and 1990. The facial nerve was anatomically preserved in 99.2% of the patients, and 90% of all the patients had grade 1 or 2 facial nerve function 1 year after surgery. Long-term facial function was inversely correlated with the size of tumor (chi-squared, p < 0.02) and was not related to the side of tumor, the age and sex of the patient, or the surgical approach. In a comparison among tumor groups matched for size, no statistically significant difference in facial nerve outcome between the translabyrinthine and retrosigmoid approaches was detected. The proximal facial nerve stimulation threshold at the end of surgical removal was predictive of long-term facial nerve function (analysis of variance, p < 0.02). At 1 year, 98% (87 of 89) of the patients with electrical thresholds of 0.2 V or less had grade 1 or 2 facial nerve function compared with only 50% (8 of 16) of those with thresholds between 0.21 and 0.6 V. In the era of cranial nerve monitoring, patients can be better advised about long-term facial nerve outcome after surgical intervention. Preoperatively, the size of the tumor is the most critical factor in predicting long-term facial function. Postoperatively, the proximal seventh nerve stimulation threshold at the end of the surgical procedure can be used as one prognostic measure of long-term facial nerve function.

Adult↗
PubMed2001

Laser, fibrin glue, or suture repair of peripheral nerves: a comparative functional, histological, and morphometric study in the rat sciatic nerve.

OBJECT: This study was undertaken to evaluate CO2 laser-assisted nerve repair and compare it with nerve repair performed with fibrin glue or absorbable sutures. METHODS: In eight rats, the sciatic nerve was sharply transected and approximated using two 10-0 absorbable sutures and then fused by means of CO2 milliwatt laser welding (power 100 mW, exposure time 1 second per pulse, spot size 320 microm), with the addition of a protein solder (bovine albumin) to reinforce the repair site. The control groups consisted of eight rats in which the nerves were approximated with two 10-0 absorbable sutures and subsequently glued using a fibrin sealant (Tissucol), and eight rats in which the nerves were repaired using conventional microsurgical sutures (four to six 10-0 sutures in the perineurium or epineurium). Evaluation was performed 16 weeks postsurgery and included the toe-spreading test and light microscopy and morphometric assessment. The motor function of the nerves in all groups showed gradual improvement with time. At 16 weeks, the motor function was approximately 60% of the normal function, and there were no significant differences among the groups. On histological studies, all nerves revealed various degrees of axonal regeneration, with myelinated fibers in the distal nerve segments. There were slight differences in favor of the group treated with laser repair, in terms of wound healing at the repair site. In all groups, the number of axons distal to the repair site was higher compared with those proximal, but the axon diameter was significantly less than that in control nerves (p < 0.05). There were no significant differences in the number, density, or diameter of the axons in the proximal or distal nerve segments among the three nerve repair groups (p < 0.05), although there was a trend toward more and thicker myelinated axons in the distal segments of the laser-repaired nerves. CONCLUSIONS: It was found that CO2 laser-assisted nerve repair with soldering is at least equal to fibrin glue and suture repair in effectiveness in a rodent model of sciatic nerve repair.

Animals↗
PubMed2006

Approach to the cervical portion of the vagus nerve via the posterior cervical triangle: a cadaveric feasibility study with potential use in vagus nerve stimulation procedures.

OBJECT: The authors describe a technique in which the cervical portion of the vagus nerve is exposed during procedures such as neuroma resection or, more commonly, during the placement of a vagus nerve stimulator. METHODS: To test their hypothesis that a posterolateral approach to the vagus nerve may be feasible and efficacious, the authors performed dissection of the left-sided vagus nerve in 13 adult cadavers. The carotid sheath was exposed via the posterior cervical triangle, and the vagus nerve was identified posterolaterally. Measurements were made of the length of available nerve, and the anatomical approach was documented. As part of a comparison study regarding the available length of nerve, the authors exposed the left vagus nerve in five additional adult cadavers via a standard anterior approach to the carotid sheath, and compared the results obtained with each technique. A mean length of 12 cm of the vagus nerve was isolated when using the posterior approach to the carotid sheath, whereas a mean length of 11 cm of the nerve was documented when using the anterior approach. With the aforementioned posterior approach, no obvious injury occurred to the vagus nerve or other local neurovascular structures such as the spinal accessory nerve. CONCLUSIONS: Evaluation of the findings obtained in the present cadaveric study showed that a posterior approach to the vagus nerve is feasible. The technique for posterior exposure of the carotid sheath may prove useful in surgical exposures of the vagus nerve when a standard anterior method is not possible.

Aged↗
PubMed2004

[Nerve exploration and decompression for traumatic recurrent laryngeal nerve injuries induced by thyroid gland surgery].

OBJECTIVE: To show the findings of recurrent laryngeal nerve injury exploration and find out therapeutic effects, indications and timing of nerve decompression for traumatic recurrent laryngeal nerve injury induced by thyroid gland surgery. METHODS: In this study there were 87 patients with recurrent laryngeal nerve injury, including 65 for nerve exploration and 22 for nonsurgical treatment. During nerve exploration, the types, severity of laryngeal nerve injuries and laryngeal muscular mass were studied. Nerve decompression was performed in these 14 patients whose compressing sutures or compression due to cicatricial hypertrophy were received nerve decompression. RESULTS: Injuries caused by thyroid gland operations mostly are of suture ligation (43%) and nerve severance (48%); simple scar compression was found only in 6 cases (9%). Atrophy of the laryngeal muscles was not very serious in patients with a course less than 6 months. In 10 patients with a course less than three months, nerve decompression restored normal functional abductor and abductor motion of the vocal cord in 9 patients and had no effects in one. Although functional motion of vocal cord was not seen in one case with a course less than 3 months and 4 cases between 3 and 5 months, the mass and tension of the reinnervated vocal cord became much the same as the contralateral normal vocal cord, thus resuming symmetric vibration of the vocal cords and physiological phonation. Although nonsurgical treatment improved severe hoarseness, it didn't restore normal functional motion of the vocal cord and normal voice. CONCLUSIONS: Nerve exploration showed a primary rule for recurrent laryngeal nerve injury induced by thyroid gland surgery. Early and mid-stage recurrent laryngeal nerve exploration and decompression may restore normal motion of the glottis, and it suggested laryngeal delayed reinnervation may help patients with a course more than 6 months.

Adult↗
PubMed1993

[Reconstruction for brachial injury by the accessory nerve--anatomy of the accessory nerve and its innervation of the trapezius--Japan].

At present reconstruction of not only elbow function, but also wrist and fingers function is possible for totally paralysed root avulsion type of brachial plexus injuries by means of multiple nerve transfers and free muscle transplantation. Although denervation of the trapezius muscle may be a problem, the accessory nerve is used as the donor nerve for reconstruction. Forty-seven cadaver dissections were performed to determine the innervation of the trapezius. In 98% of the regions, branches of the accessory nerve or the cervical nerves were found to be directly innervated with the accessory nerve in the posterior triangle of the neck without anastomosis. This study came to the conclusion that it was possible to use the accessory nerve as the donor nerve without paralysis of the upper part of the trapezius, if the accessory nerve was used at an adequate point. Since the course of the accessory nerve is similar to one of the cervical nerve in the posterior triangle of the neck, it is difficult to distinguish them. The layer of the course and the great auricular nerve at the posterior margin of the sternocleidomastoid are reference points of the accessory nerve and the cervical nerves.

Accessory Nerve↗
PubMed1993

A quantitative study of nerve fibers in the human facial nerve.

The facial and intermediate nerves were quantitatively evaluated in seven patients who died from systemic malignancies not involving the facial nerve. In addition, five of the specimens were also qualitatively evaluated by measuring the total and axon diameters of the facial and intermediate nerve fibers. In two cases the facial nerve fibers were counted at five different levels. The total number of myelinated nerve fibers in the facial nerve varied from 7500 to 9370. The total number of myelinated nerve fibers in the intermediate nerve varied between 3120 and 5360. The peak diameter of the facial nerve axon was between 4 and 6 microns, and was between 2 and 3 microns in the intermediate nerve. When comparing nerve segments at different anatomical levels, the largest amount of nerve fibers was found at the level of the middle mastoid portion. However, this number did not reach the amount of nerve fibers counted in the internal acoustic meatus.

Adult↗
PubMed1983

Pathology and pathogenesis of predilective sites of nerve damage in leprous neuritis. Nerves in the arm and the face.

A very brief review of the literature on the clinicopathological aspects of leprosy is given; mainly through references. The salient features of the two main types of leprosy--tuberculoid and lepromatous--are presented in a Table. The surgical and pathological findings are briefly described and the pathogenesis of involvement of the facial nerve (a motor nerve) is discussed. On the basis of (i) the severe histopathologic changes (degeneration) of the most distal part of the zygomatic branch of the facial nerve (innervating the orbicularis oculi), with sparing of the roots of all branches and the trunk of the nerve; (ii) the concurrent loss of cutaneous sensations in the territory of the maxillary division of the trigeminal nerve (the region of the zygoma and the lower eyelid); and (iii) the close approximation or even anastomoses occurring between the ultimate branches of these two nerves, it is postulated that paralysis of orbicularis oculi occurs secondarily to the sensory nerve damage, i.e. due to spread of infection from the sensory branches of the trigeminal to the motor branches of the facial nerve. The surgical and pathological findings of the nerves in the arm, especially the ulnar and the median and their branches are described, in tuberculoid and lepromatous leprosy. The forms of nerve degeneration, the occasional axon regeneration, and the role of the Schwann cell in harbouring the bacilli, are illustrated. The lysosomal enzyme activity in the Schwann cells of nerve fibres, particularly of unmyelinated fibres which preferentially phagocytose the M. leprae, and their role, albeit not very successful, in degrading the bacilli and controlling the infection, are also stressed, through light and electronmicrographs. The constellation of secondary factors of the terrain operating to produce further damage to primarily diseased nerves, is discussed. These factors include indirect compression from unyielding fibroosseous tissues, minor traumata, stretching of the nerves, and their exposure to lower temperatures in subcutaneous tissues.

Facial Nerve↗
PubMed1992

Expression of the pro-opiomelanocortin gene in dorsal root ganglia, spinal cord and sciatic nerve after sciatic nerve crush in the rat.

Neuropeptides related to alpha-melanocyte-stimulating hormone (alpha-MSH) stimulate nerve outgrowth following peripheral nerve injury and may play an important physiological role in peripheral nerve regeneration. The mechanism of action underlying the neurotrophic effect of pharmacologically administered alpha-MSH is unknown. Here we investigate the hypothesis that reexpression of the proopiomelanocortin (POMC) gene, the prohormone of alpha-MSH/adrenocorticotropic hormone (ACTH)-like peptides, is part of the endogenous repertoire of peripheral nerve responses following injury. The effect of sciatic nerve crush on the expression of POMC mRNA between 0.5 h and 14 days after crush was investigated using polymerase chain reaction (PCR) and Northern blot analysis. The presence of a POMC transcript in dorsal root ganglia (DRG), spinal cord and in the sciatic nerve at the crush site could be demonstrated in both control and lesioned animals by PCR using primers located in exon 1 and 3 of the POMC gene. Minute quantities of two POMC transcripts (1200 nt and 800 nt) could be detected by Northern blot analysis of total RNA prepared from DRG, spinal cord and the sciatic nerve of control animals and of animals subjected to nerve crush. POMC mRNA expression was, however, not increased following nerve crush. Probes specific for exons 1 and 2 or specific for exon 3 of the POMC gene were employed to demonstrate that the 800 nt transcript represents the truncated POMC mRNA previously shown to be present in extra-pituitary tissue. The larger 1200 nt transcript comigrates with the full length POMC mRNA expressed in the pituitary gland. The present results demonstrate the expression of small amounts of POMC mRNA in all compartments of the sciatic nerve. The absence of an induction of POMC expression in response to nerve crush suggests that the stimulating effect of exogenously applied alpha-MSH does not mimic a POMC derived neurotrophic peptide induced in the nerve following nerve injury.

Animals↗
PubMedDate not supplied

Locating the target nerve and injectate spread in rabbit sciatic nerve block.

BACKGROUND AND OBJECTIVES: The purpose of this study is to determine how close the needle tip is placed to the target nerve using a nerve stimulator and to determine how far the injectate spreads in percutaneous nerve blocks. METHODS: Twenty-four sciatic nerves of New Zealand white rabbits were located with a 2-dimensional needle manipulator and a nerve stimulator (pulse width: 100 micros for group I, 250 micros for group II). The stimulation current required to elicit a motor response for each insertion depth of the needle and the nerve-needle distance at which the required current reached the minimum were measured. Another 10 sciatic nerves were located manually using a nerve stimulator and neurolyzed with a mixed solution of 5% phenol and Indian ink (100 microL). RESULTS: The nerve-needle distance was in the range of -1.2 mm to +2.8 mm in group I (1.1 +/- 0.9 mm [mean +/- standard error] in absolute value) and -0.2 mm to +4.8 mm (2.2 +/- 1.7 mm [mean +/- standard error] in absolute value) in group II (positive values signify the center of the beveled surface is past the nerve), when the stimulation current reached the minimum (average minimum current: 0.47 mA in group I, 0.37 mA in group II). Indian ink spread over a significant distance (25.4 +/- 0.5 mm [mean +/- standard error]; range, 19-31 mm) longitudinally within the perineural tissue, and axonal degeneration was observed linearly at the peripheral portion of the nerve fascicle in a similar pattern as Indian ink spread. CONCLUSIONS: The target nerve was located within 5 mm from the needle with less than 0.5-mA stimulation current. The injectate spread to more than 20 mm on average even when a small volume (100 microL) of the injectate was injected in rabbit sciatic nerves.

Animals↗
PubMed2000

Peripheral nerve regeneration across an 80-mm gap bridged by a polyglycolic acid (PGA)-collagen tube filled with laminin-coated collagen fibers: a histological and electrophysiological evaluation of regenerated nerves.

We evaluated peripheral nerve regeneration across an 80-mm gap using a novel artificial nerve conduit. The conduit was made of a polyglycolic acid (PGA)-collagen tube filled with laminin-coated collagen fibers. Twelve beagle dogs underwent implantation of the nerve conduit across an 80-mm gap in the left peroneal nerve. In four other dogs used as negative controls, the nerve was resected and left unconnected. Histological observation showed that numerous unmyelinated and myelinated nerve fibers, all smaller in diameter and with a thinner myelin sheath than normal nerve fibers, regrew through and beyond the gap 12 months after implantation. The distribution of the regenerated axonal diameters was different from that of the normal axonal diameters. Compound muscle action potentials, motor evoked potentials, and somatosensory evoked potentials were recorded in most animals 3 months after implantation. Peak amplitudes and latencies recovered gradually, which indicating the functional establishment of the nerve connection with the target organs. In addition to the ordinary electrophysiological recoveries, potentials with distinct latencies originating from Aalpha, Adelta and C fibers became distinguishable at the 6th lumbar vertebra following stimulation of the peroneal nerve distal to the gap 12 months after implantation. The pattern of walking without load was restored to almost normal 10-12 months after implantation. Neither electrophysiological nor histological restoration was obtained in the controls. Our nerve conduit can guide peripheral nerve elongation and lead to favorable functional recovery across a wider nerve gap than previously reported artificial nerve conduits.

Animals↗
PubMed1999

Sympathetic nerve sprouting fails to occur in the trigeminal ganglion after peripheral nerve injury in the rat.

Peripheral nerve injury induces sprouting of sympathetic nerve fibers in dorsal root ganglia after spinal nerve injury. In the present study, we sought to determine the extent of intraganglionic noradrenergic sprouting in the trigeminal system. The inferior alveolar nerve, a major branch of the mandibular division, or the infraorbital nerve of the maxillary division was either ligated or chronically constricted in Sprague-Dawley rats and recovery permitted for either 2-3 or 6-9 weeks. In some animals both nerves were injured. Using immunohistochemistry with tyrosine hydroxylase antibodies, we found no signs of sympathetic nerve fiber sprouting in the trigeminal ganglion after injury. In contrast, sciatic nerve injury in rat littermates induced a widespread autonomic nerve outgrowth in affected DRGs. Thus, sensory ganglion sympathetic nerve sprouting does not seem to be a general outcome of PNS injury, but is restricted to certain specific locations. Sympathetic nerve fiber networks that surround primary sensory neurons have been suggested to form a structural basis for interactions between the sympathetic and sensory nervous systems after PNS injury. Such interactions, sometimes resulting in paraesthesia or dysaesthesia in patients, appear to be less common in territories innervated by the trigeminal nerve than in spinal nerve regions. The lack of injury-induced intraganglionic sympathetic sprouting in the trigeminal ganglion may help to explain this observation.

Animals↗
PubMed1985

Classical conditioning of a flexor nerve response in spinal cats: effects of tibial nerve CS and a differential conditioning paradigm.

Previous studies have shown flexor nerve response increases produced by classical conditioning procedures in spinal cats when the conditioned stimulus (CS) was delivered to the superficial peroneal nerve and the unconditioned stimulus (US) was delivered to the ankle skin. In this study, these effects were produced when the CS was delivered to the whole tibial nerve or to the medial plantar branch. The finding that response increases followed by extinction effects could be obtained when either the superficial peroneal or the tibial nerve was utilized allowed the assessment of the effects of a differential conditioning paradigm. The responses to CS-US presentations on the superficial peroneal nerve increased, whereas responses to CS presentations on the tibial nerve remained unchanged. However, lack of extinction effects in the superficial peroneal data suggested that stimulation of the tibial nerve potentiated superficial peroneal evoked responses. Furthermore, responses evoked by stimulation of either nerve increased when paired trials were given on the tibial nerve. These data demonstrate that stimulation of the tibial nerve potentiates responses to superficial peroneal nerve stimulation but that superficial peroneal nerve stimulation has no effect on responses to CS presentations to the tibial nerve.

Animals↗
PubMedDate not supplied

Engineering an improved acellular nerve graft via optimized chemical processing.

The long-term goal of our research is to engineer an acellular nerve graft for clinical nerve repair and for use as a model system with which to study nerve-extracellular matrix interactions during nerve regeneration. To develop this model acellular nerve graft we (1) examined the effects of detergents on peripheral nerve tissue, and (2) used that knowledge to create a nerve graft devoid of cells with a well-preserved extracellular matrix. Using histochemistry and Western analysis, the impact of each detergent on cellular and extracellular tissue components was determined. An optimized protocol was created with the detergents Triton X-200, sulfobetaine-16, and sulfobetaine-10. This study represents the most comprehensive examination to date of the effects of detergents on peripheral nerve tissue morphology and protein composition. Also presented is an improved chemical decellularization protocol that preserves the internal structure of native nerve more than the predominant current protocol.

Animals↗
PubMed1977

Electron microscopy of the mouse optic nerve: a quantitative study of the total optic nerve fibers.

The total number of myelinated and unmyelinated nerve fibers was counted in a montage of electron micrographs prepared to cover the entire profile of the mouse optic nerve in transverse section. Many astrocytic processes form a barrier structure all around the optic nerve. As a whole, the mouse optic nerve consists of one fascicle where the nerve fibers, the glia cells and their processes, and the capillaries are fitted closely together to fill substantially all of the available space. No tissue space accompanied with connective tissue septa penetrates into the fascicle, except for those situated around the arteriole and venule. The total number of 64,746 myelinated nerve fibers in the optic nerve in one side was counted. This corresponds to about 98.8% of the total number of the optic nerve fibers. The total number of 807 unmyelinated nerve fibers was also counted. This corresponds to about 1.2% of the total nerve fibers. The external diameter of every myelinated fiber, including the myelin sheath, was measured on the montage micrograph and its frequency distribution was examined. The diameter of the myelinated fibers ranges from 0.3 to 4.2 mu and its mean value is 0.96 mu. The frequency distribution of fiber diameter is unimodal with a peak at 0.7 to 0.9 mu. A regional heterogeneity in fiber size is found in the optic nerve. The nerve fibers in the peripheral area of the nerve are relatively small and uniform in diameter, whereas those in the central area show a fairly wide range in diameter.

Animals↗
PubMed2006

[Anatomic study of the hypoglossal nerve in hypoglossal-facial nerve anastomosis].

OBJECTIVE: To determine the optimal position of hypoglossal nerve in hypoglossal-facial nerve anastomosis and the eligibility of hypoglossal-facial nerve anastomosis with the cervical loop. METHODS: The cervical course and adjacent structures of the hypoglossal nerve were observed on 21 adult cadavers. The hypoglossal nerve and facial nerve were taken from 3 fresh specimens, and the number of the fasciculus and the cross-sectional area of the nerve were measured. RESULTS: The facial nerve trunk were monofascicular with a cross-sectional area of 5.1-/+0.2 (range 4.6-5.7) mm(2). The number of the fasciculus and the cross-sectional areas of the nerve trunk and the fasciculus were 1.6-/+0.8 (range 1-4) mm(2) , 7.5-/+0.7 mm(2) (range 6.8-8.0) mm(2), and 4.7-/+0.6 (4.1-5.5) mm(2), respectively, at the proximal segment of the hypoglossal nerve, 3.6-/+0.5 (1-5) mm(2) , 5.6-/+0.5 (4.9-6.1) mm(2) , and 1.6-/+0.4 (0.9-2.2) mm(2) at the distal segment, and 2.4-/+0.8 (1-3) mm(2), 1.1-/+0.7 (0.6-2.2) mm(2), and 0.5-/+0.3 (0.3-1.2) mm(2) at the cervical loop. CONCLUSION: The cervical loop is inadequate for facial nerve anastomosis and the proximal segment is large enough to allow partial harvesting of the hypoglossal nerve for neurotisation of the facial nerve.

Anastomosis, Surgical↗
PubMed2006

[An effect of the peripheral nerve allograft with subcutaneous preservation at different times on the nerve regeneration].

OBJECTIVE: To study an effect of the peripheral nerve allograft with subcutaneous preservation at different times on the sciatic nerve regeneration in rats. METHODS: Fifty-five Wistar rats were used in this experiment, which were randomly divided into the following 5 groups: the experimental groups (Groups A, B, C, 10 rats), the control group (Group D, 10 rats), and the donor group (Group E, 15 rats). In the experimental groups, a 15-mm segment of the sciatic nerve harvested from the donors was separately inserted into the subcutaneous compartment on the left thigh after the 1-week (Group A), 2-week (Group B), and 3-week (Group C) preservation; the segment of the sciatic nerve in the subcutaneous compartment was removed and transplanted into a 10-mm defect of the right sciatic nerve, which was made immediately. In Group D, a 10-mm sciatic nerve defect was made and immediately repaired in situ on the right thigh. The function of the sciatic nerve was evaluated by the sciatic functional index (SFI) at 2, 4, 6, 8, 10 and 12 weeks after operation. The histological and electrophysiological examinations were performed at 12 weeks after operation. RESULTS: After operation, SFI decreased gradually at 12 weeks after operation, SFI in Groups A and D was at the minimal level and had a significant difference compared with that in Groups B and C (P < 0.05). There was no significant difference between Group A and Group D. A large number of the myelinated nerve fibers and a small number of the unmyelinated nerve fibers were regenerated in Groups A and D. The number and the structure of the regenerated nerve were similar to the normal ones. The number and the size of the regenerated axon had a significant difference compared with those in Groups B and C (P < 0.05). There was no significant difference between Group A and Group D. The conduction velocity and the latent period of the motor nerve had significant differences between Groups A and D and Groups B and C (P < 0.05), and there was no significant difference between Group A and Group D. CONCLUSION: The nerve allograft with a 1-week subcutaneous preservation can promote nerve regeneration better.

Animals↗