Hemihypoglossal-facial nerve anastomosis in treating unilateral facial palsy after acoustic neurinoma resection

Motor reinnervation of a denervated muscle by using a sensory nerve: an experimental study on gluteus maximus muscle of the rat

PURPOSE

This study aimed at developing a new muscle reinnervation technique using a sensory nerve.

METHODS

We attempted innervation of the rat gluteus maximus muscle using the lateral femoral cutaneous nerve (LFCN). We placed the gluteus maximus muscle into the fibroadipose tissue in the distribution of the LFCN in 24 rats. In one group, the original innervation remained intact. In the second and third groups, the muscles were denervated, and in the third group, the proximal end of the nerve to the gluteus maximus was sutured to the distal end of the divided LFCN. We compared muscle reinnervations of the groups by using electrophysiologic evaluation of the muscle contractions, light microscope evaluation of the axonal regenerations, and scanning electron microscope evaluation of the actin-myosin structures of the muscles at the end of an elapsed waiting period.

RESULTS

At the end of electrophysiologic evaluation, the mean area of compound muscle action potentials measured in group 1 was 3.8 ms/mV; in group 2, 0.0; and in group 3 (experimental group), 0.5. Axonal regeneration was observed distal to the coaptation, and actin-myosin structures were mostly spared in group 3.

CONCLUSIONS

This study explored the feasibility of a new flap prefabrication method that aims at developing reinnervation of a denervated muscle by means of a sensory nerve. In light of histologic and electrophysiologic findings, this type of reinnervation is possible.

Intratemporal Facial Nerve Transfer With Direct Coaptation to the Hypoglossal Nerve

OBJECTIVE

To evaluate functional recovery after facial-hypoglossal nerve transfer with direct coaptation of the intratemporal part of the facial nerve.

STUDY DESIGN

Retrospective study.

SETTING

University-based tertiary referral center.

PATIENTS

Nine patients who underwent facial-hypoglossal transfer surgery between 2001 and 2006 to treat a unilateral complete facial nerve palsy.

INTERVENTION

The facial nerve is mobilized in the temporal bone, transsected at the second genu, transferred and directly coaptated to a partially incised hypoglossal nerve.

MAIN OUTCOME MEASURES

The House-Brackmann grading system was used to evaluate facial nerve reinnervation. Tongue atrophy and movements were documented. Quality of life related to facial function was assessed using the validated Facial Disability Index.

RESULTS

A House-Brackmann Grade III (86%) was achieved in six patients, and Grade IV (14%) in one patient with an average follow-up of 22 months (range, 12-48 mo). Two patients had a follow-up of less than 12 months after surgery, and reinnervation was still in progress. In none of the patients who were operated on was tongue atrophy or impaired movement observed. Postoperative Facial Disability Index scores (mean, 71.8 +/- standard deviation [SD] 10.6) for physical functioning and social functioning (mean, 85.7 +/- SD 9.8) were increased for all patients when compared with preoperative scores (mean, 28.6 +/- SD 9.0; mean, 37.7 +/- SD 14.4, respectively).

CONCLUSION

The facial-hypoglossal nerve transfer with direct coaptation of the intratemporal part of the facial nerve offers good functional results with low lingual morbidity and improved quality of life. The technique is straightforward, relatively simple, and should be considered as first option for reanimation of traumatic facial nerve lesions.

Role of the trigeminal nerve in regrowth of hypoglossal motoneurons after hypoglossal-facial anastomosis

Conclusion. Functional recovery of facial muscles following hypoglossal-facial anastomosis (HFA) may be dependent not only on sensory information, relayed via the trigeminal nuclei to the hypoglossal nucleus, but also on extratrigeminal fibers, originating from the hypoglossal nucleus that travel in the infraorbital nerve (ION). This fact helps to explain the ability of hypoglossal neurons, after HFA, to induce contractions of muscles originally innervated from other nervous structures. Objective. The aim of the study was to better understand the role of the trigeminal nerve in reinnervation of facial muscles by hypoglossal motoneurons following HFA. Materials and methods. Central afferences of the ION were analyzed in rats by labeling the exposed nerve with horseradish peroxidase (HRP), whereas central organization of the efferent projections to the vibrissal area was analyzed by labeling the whisker pad muscles of the rat with a 5% solution of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil) in N,N-dimethylformamide. Results. The results show that extratrigeminal fibers, originating in the hypoglossal nucleus, travel along the ION. Retrograde tracing applied to ION or injected into the whisker pad showed labeled neurons in the Pr5 nucleus and all Sp5 trigeminal subnuclei. Small labeled neurons (10-15 microm diameter; 10-12 neurons per section), were also found in the hypoglossal nucleus.

Concepts of nerve regeneration and repair applied to brachial plexus reconstruction

Brachial plexus injury is a serious condition that usually affects young adults. Progress in brachial plexus repair is intimately related to peripheral nerve surgery, and depends on clinical and experimental studies. We review the rat brachial plexus as an experimental model, together with its behavioral evaluation. Techniques to repair nerves, such as neurolysis, nerve coaptation, nerve grafting, nerve transfer, fascicular transfer, direct muscle neurotization, and end-to-side neurorraphy, are discussed in light of the authors' experimental studies. Intradural repair of the brachial plexus by graft implants into the spinal cord and motor rootlet transfer offer new possibilities in brachial plexus reconstruction. The clinical experience of intradural repair is presented. Surgical planning in root rupture or avulsion is proposed. In total avulsion, the authors are in favor of the reconstruction of thoraco-brachial and abdomino-antebrachial grasping, and on the transfer of the brachialis muscle to the wrist extensors if it is reinnervated. Surgical treatment of painful conditions and new drugs are also discussed.

[Hypoglossal facial anastomosis as a solution to a total peripheral facial palsy. Our experience]

Hypoglossal-facial anastomosis was performed in four patients with total peripheral facial palsy after removal of cerebellopontine tumors (three patients with neurinoma) and pontine aneurysm (one patient). The anastomosis was performed after a period of 3 months to one year from surgery. The results obtained, concerning the facial activity, were clinically valued according to the tests used (questionnary, and the House-Brackmann paralysis index); the EnOG was used for its electrophysiological assessment. The follow-up period was 4 years with a good facial recovery in three patients and poor in one (class V, 27% in ENoG). We observe that the improvement in function greatly depends on the early surgical process performance.

Side-to-end hypoglossal-facial anastomosis via transposition of the intratemporal facial nerve

The technique of facial nerve repair with side-to-end hypoglossal-facial anastomosis is presented and evaluated in five patients who were operated on for facial nerve paralysis after acoustic schwannoma surgery, or had cranial base trauma. The end-to-end hypoglossal-facial anastomosis is accompanied by hemilingual paralysis, with difficulty in swallowing, chewing and speaking. In this new technique, the facial nerve is mobilised in the temporal bone, transected at the second genu and transposed to the hypoglossal nerve where a tensionless side-to-end anastomosis is performed. The hypoglossal nerve is transected in oblique fashion to about one third of its circumference. We were able to achieve a tensionless anastomosis in all patients. The idea is to bring about re-innervation of the previously denervated tissue via a collateral sprouting of axons of the donor nerve through the site of coaptation without sacrificing the innervation of the donor nerve's original targets. With side-to-end hypoglossal-facial anastomosis, two patients attained a House- Brackmann grade of III (one of them with independent movement of eyelids and mouth); one achieved grade IV, another grade V and grade VI. No patient had hemilingual atrophy nor any problems associated with swallowing or chewing.

End-to-side nerve graft for facial nerve reconstruction

Reconstruction of multiple branches of the facial nerve by sural nerve graft using end-to-side nerve suture was performed successfully on a patient with advanced parotid tumor. In this technique, one end of the grafted nerve is sutured with the stump of the facial nerve trunk in an end-to-end manner. Epineural windows are made on the nerve graft, and the distal stumps of the facial nerve branches (temporal, zygomatic, and buccal branches) are sutured with the graft in an end-to-side manner. Functional recovery of all branches and satisfactory facial expression were obtained within 2 years postoperatively. Axonal regeneration through the graft was confirmed by electrodiagnosis. Regeneration through the anastomosis at the stump of the facial nerve trunk using this technique is more efficient than conventional cable grafting, and the length of the nerve required is minimal. This technique may be a useful option for facial nerve reconstruction managing multiple branches.

Nerve transfers for severe brachial plexus injuries: a review

Nerve transfer procedures are increasingly performed for repair of severe brachial plexus injury (BPI), in which the proximal spinal nerve roots have been avulsed from the spinal cord. The procedure essentially involves the coaption of a proximal foreign nerve to the distal denervated nerve to reinnervate the latter by the donated axons. Cortical plasticity appears to play an important physiological role in the functional recovery of the reinnervated muscles. The author describes the general principles governing the successful use of nerve transfers. One major goal of this literature review is to provide a comprehensive survey on the numerous intra- and extraplexal nerves that have been used in transfer procedures to repair the brachial plexus. Thus, an emphasis on clinical outcomes is provided throughout. The second major goal is to discuss the role of candidate nerves for transfers in the surgical management of the common severe brachial plexus problems encountered clinically. It is hoped that this review will provide the treating surgeon with an updated list, indications, and expected outcomes involving nerve transfer operations for severe BPIs.

Alternative approach using the combined technique of nerve crossover and cross-nerve grafting for reanimation of facial palsy

An alternative approach, using a combination of nerve crossover and cross-nerve grafting technique in a single-stage procedure, was developed for the reconstruction of reversible facial palsy. This combined technique provides some benefits such as early facial reanimation resulting from the single-stage procedure, less morbidity and sufficient innervation with an application of the end-to-side anastomosis method, and efficient neural regeneration due to coaptation of the intratemporal facial nerve. Facial nerve rehabilitation, based on double innervation by hypoglossal and contralateral healthy facial nerves, takes advantage of reliable and physiological facial reanimation.

One-stage Removal of Residual Intracanalicular Acoustic Neuroma and Hemihypoglossal-intratemporal Facial Nerve Anastomosis: Technical Note

OBJECTIVE AND IMPORTANCE

Incomplete removal of residual intracanalicular tumor and injury to the facial nerve are the main problems associated with surgery of large acoustic neuromas via the retromastoid suboccipital approach. In patients with residual or recurrent intracanalicular neuromas, the translabyrinthine approach is the preferred surgical route, allowing complete tumor removal; it may eventually also be used for exposure of the intratemporal portion of the facial nerve for a hemihypoglossal-facial nerve anastomosis when a postoperative facial palsy exists This one-stage procedure has not been described previously.

CLINICAL PRESENTATION

Three patients with postoperative facial palsy and residual intracanalicular tumor after surgical removal of a large acoustic neuroma via the retromastoid suboccipital approach underwent reoperation via the translabyrinthine approach and one-stage removal of the residual tumor and hemihypoglossal-facial nerve anastomosis. All three patients had a complete facial palsy of House-Brackmann Grade VI and a residual tumor of 8 to 12 mm.

TECHNIQUE

A classic translabyrinthine approach was used to open the internal auditory canal and remove the residual intracanalicular tumor. The facial nerve was exposed in its mastoid and tympanic parts, mobilized, and transected; then, the long nerve stump was transposed into the neck and used for an end-to-side anastomosis into the hypoglossal nerve. The operation resulted in variable improvement of the facial muscle function up to Grade III (one patient) and Grade IV (two patients).

CONCLUSION

Reoperation via the translabyrinthine approach is indicated for removal of residual intracanalicular acoustic neuroma and realization of a hypoglossal-facial nerve anastomosis in a single procedure. It is suggested that this type of anastomosis may also be used during the initial operation for acoustic neuroma removal when the facial nerve is inadvertently sectioned.

Reinnervation of denervated muscle in a split-nerve transfer model

This study was performed to quantify the reinnervation of denervated muscle in a split-nerve transfer model and to determine any possible downgrading effects on the donor nerve and its end organ. Fifty-four adult Wistar rats weighing 200 to 250 g were used. The experimental design consisted of two groups. The motor nerve branch to the anterior tibial muscle and gastrocnemius muscle of the right hind limb were dissected in all rats. In the experimental group (N = 36), the motor nerve branch of the tibial nerve to the gastrocnemius muscle was exposed, cut, and ligated. The motor nerve branch to the anterior tibial muscle was split and transected longitudinally, and the medial half was routed posteriorly. End-to-end neural anastomosis was performed between this medial half of the split nerve and the distal stump of the gastrocnemius nerve. In the control group (N = 18), while the same surgical preparation was performed, the motor nerve branch to the anterior tibial muscle and gastrocnemius nerve were exposed and transected, and the nerve endings were ligated, but neural anastomosis was not performed between these nerves. The left hind limb of all rats served as a normal comparison side without any surgical intervention. Both of the groups were divided into three subgroups (12 rats each for the experimental groups and 6 rats each for the control group) to evaluate the results after periods of 1, 3, and 6 months. Electromyography, light microscopic and morphometric examination, and muscle weight measurements were used to document the results. Although stimulation of the peroneal and tibial nerves did not produce any compound muscle action potential (CMAP) recordings from either the anterior tibial or the gastrocnemius muscle in the control group, the normalized CMAP areas of the tibial nerve were (mean +/- standard deviation) 16.2 +/- 30.8% in the 1-month group, 63.4 +/- 34.7% in the 3-month group, and 72.4 +/- 16.3% in the 6-month group. For the peroneal nerve, the normalized CMAP areas were 17.0 +/- 32.2%, 53.4 +/- 29.4%, and 54.4 +/- 14.5% for the 1-, 3-, and 6-month groups in the experimental groups respectively. A high number of regenerating myelinated nerve fibers was identified in the distal part of the coapted motor nerve branch to the gastrocnemius muscle. The average number of myelinated fibers in the lateral half of the split nerve in the experimental group was 15,108 fibers per square millimeter, 14,167 fibers per square millimeter, and 19,830 fibers per square millimeter at months 1, 3, and 6 respectively. The average number of fibers proximal to the nerve anastomotic site was 15,423 fibers per square millimeter, 19,200 fibers per square millimeter, and 20,774 fibers per square millimeter. Distal to the nerve anastomotic site, the number of myelinated fibers was 17,941 fibers per square millimeter, 18,885 fibers per square millimeter, and 18,895 fibers per square millimeter at 1, 3, and 6 months respectively. There were no myelinated fibers in the control group sections. There were significant differences in muscle weight between the experimental and control groups at the end of month 6. The difference between the experimental side and the untouched normal healthy side was not significant in the weight measurements of both muscles. The results show acceptable reinnervation by split-nerve transfer with minimal functional impairment of the donor muscle. This study confirms that split-nerve transfer is a reliable method of reconstruction for paralyzed muscle with minimal donor area morbidity.

Reanimation of the paralyzed face by indirect hypoglossal-facial nerve anastomosis

BACKGROUND

The results of indirect hypoglossal facial nerve anastomosis with interposition of a free nerve graft, end-to-end to the periferal facial nerve stump, and end-to-side to the hypoglossal nerve are prospectively evaluated. This technique is supposed to overcome loss of hypoglossal function.

METHODS

Tongue function in 39 consecutive patients and facial reanimation in 29 patients who completed 24 months follow-up were assessed. Facial nerve function was judged using the House-Brackmann (HB) grading system.

RESULTS

Tongue movements were normal in all operated on patients. Initial facial movements occurred on average 7.5 months postoperatively. The results were graded HB II in 6 (20.9%), HB III in 13 (44.6%), HB IV in 7 (24.1%), HB V in 2 (6.8%) patients, and HB VI in 1 (3.4%) patient. The results were significantly better in young patients and when a short time interval between paralysis and surgery existed.

CONCLUSIONS

Indirect hypoglossal-facial anastomosis is the preferred technique in most patients for whom the classical direct hypoglossofacial anastomosis is indicated.

Nerve transfer to the median nerve using parts of the ulnar and radial nerves in the rabbit--effects on motor recovery of the median nerve and donor nerve morbidity

In this study, motor re-innervation of the median nerve by transfer of one-third, one-half, and two-thirds of either the agonistic ulnar nerve or the antagonistic radial nerve was investigated in both extremities of 20 rabbits. Recipient median nerve: Muscle contraction force of the flexor digitorum sublimus muscle after a one-third and a one-half of the ulnar nerve transfer achieved an average of 75 and 97% muscle power respectively as compared to conventional end-to-end neurorrhaphy. Muscle contraction force after one-third or one-half of the radial nerve transfer was significantly lower (36%). Donor nerves: Extensor carpi radialis muscle or flexor carpi ulnaris muscle contraction force 6 months postoperatively demonstrated a significant decrease after a one-half ulnar nerve and a two-thirds ulnar or radial nerve transfer, but not after a one-third transfer of either radial or ulnar nerves. Histologically, the number of axons in the re-innervated median nerve and both donor nerves distal to the coaptation site seemed to follow variable patterns. It was concluded that in the rabbit use of one-third of the agonistic ulnar nerve for re-innervation of the median nerve results in useful motor recovery with negligible donor site morbidity. Clinically, this technique may offer an alternative option for proximal nerve injuries or for free functioning muscle transplantations.

Hypoglossal-facial nerve anastomosis: assessment of clinical results and patient benefit for facial nerve palsy following acoustic neuroma excision

Despite advances in neuro-otological techniques permanent complete facial palsy may still occur in up to 10% of patients undergoing removal of cerebellopontine angle tumours. Hypoglossal-facial nerve anastomosis is the procedure of choice in our unit for facial reanimation in such patients and below we report the results of hypoglossal-facial nerve anastomosis performed on 29 patients. Assessment of patient benefit from hypoglossal-facial nerve anastomosis was obtained using a questionnaire based on the Glasgow Benefit Inventory. The results showed all patients to have an improvement in their House Brackmann grade following hypoglossal-facial anastomosis with 65% achieving grade III or better. Of the 20 patients who completed the questionnaire, 18 showed a positive benefit (median score 59.5, range 40-77). There was a significant correlation (P < 0.045) between the Glasgow benefit inventory score and House Brackmann grade. Outcome was not affected by the time interval between the acoustic neuroma surgery and performing the hypoglossal-facial nerve anastomosis, sex or length of follow-up. However the Glasgow benefit score was significantly influenced by age (P = 0.023) with younger patients showing more benefit independent of improvement in facial nerve function.

Surgical anatomy for direct hypoglossal-facial nerve side-to-end "anastomosis"

OBJECT

In this study the authors investigated the histomorphometric background and microsurgical anatomy associated with surgically created direct hypoglossal-facial nerve side-to-end communication or nerve "anastomosis."

METHODS

Histomorphometric analyses of the facial and hypoglossal nerves were performed using 24 cadaveric specimens and three surgically obtained specimens of severed facial nerve. Both the hypoglossal nerve at the level of the atlas and the facial nerve just distal to the external genu were monofascicular. The number of myelinated axons in the facial nerve (7228 +/- 950) was 73.2% of those in the normal hypoglossal nerve (9778 +/- 1516). Myelinated fibers in injured facial nerves were remarkably decreased in number. The cross-sectioned area of the normal facial nerve (0.948 mm2) accounted for 61.5% of the area of the hypoglossal nerve (1.541 mm2), whereas that of the injured facial nerve (0.66 mm2) was less than 50% of the area of the hypoglossal nerve. Surgical dissection and morphometric measurements were performed using 18 sides of 11 adult cadaver heads. The length of the facial nerve from the pes anserinus to the external genu ranged from 22 to 42 mm (mean 30.5 +/- 4.4 mm). The distance from the pes anserinus to the nearest point on the hypoglossal nerve ranged from 14 to 22 mm (mean 17.3 +/- 2.5 mm). The former was always longer than the latter; the excess ranged from 6 to 20 mm (mean 13.1 +/- 3.4 mm). Surgical anatomy and procedures used to accomplish the nerve connection are described.

CONCLUSIONS

The size of a half-cut end of the hypoglossal nerve matches a cut end of the injured facial nerve very well. By using the technique described, a length of facial nerve sufficient to achieve a tensionless communication can consistently be obtained.

Hypoglossal nerve transfer for laryngeal reinnervation: a preliminary study

The hypoglossal nerve is a logical donor nerve for hemilaryngeal reinnervation because 1) its activity coincides with normal laryngeal adduction during speech and deglutition; 2) it is a large nerve with many axons; and 3) donor site morbidity is low. This method of laryngeal reinnervation has not been previously reported. Previous studies using the ansa cervicalis for reinnervation have failed to show spontaneous activity. Hypoglossal-to-recurrent laryngeal nerve anastomosis was performed on a series of 5 dogs. The vocal folds were viewed monthly, with the animals awake, by infraglottic examination through a permanent tracheostomy. One dog failed due to technical error. The remaining 4 dogs began to exhibit spontaneous vocal fold adduction within 2 to 4 months. Vocal fold motion was synchronous with spontaneous tongue motion. Complete glottic closure was seen during swallowing at 3 to 5 months. Intraglottic pressure measurements following reinnervation were normal. Hypoglossal nerve transfer appears to be capable of providing functional adduction to the paralyzed hemilarynx. The potential advantages and disadvantages of this new technique are discussed.

New technique of side-to-end hypoglossal-facial nerve attachment with translocation of the infratemporal facial nerve

OBJECT

The goal of this study was to assess the clinical results of hypoglossal-facial nerve attachment (HFA), which was primarily performed in patients following excision of tumors of the cerebellopontine angle. In six of the patients a new side-to-end procedure was used.

METHODS

The authors have performed a retrospective study of 33 patients who underwent HFA, including 24 classic end-to-end, three May, and six side-to-end procedures. For the latter procedure, a hemihypoglossal-facial nerve attachment was performed by rerouting the intratemporal facial nerve; this avoided the jump-cable graft used in May's technique. The goal of the new procedure is to reduce the incidence of morbidity due to hemilingual paralysis (difficulty in chewing, speaking, and swallowing). The incidence of hemilingual paralysis was evaluated based on the findings of a questionnaire that was completed by the patients. The patient's facial mobility was assessed using the House and Brackmann grading system and the author's analytic scoring system.

CONCLUSIONS

The HFA offers good functional results. Of the 28 cases evaluated, nine had House and Brackmann Grade III, 17 Grade IV, and only two Grade V at 18 months. When the new technique of side-to-end hemihypoglossal-facial nerve attachment was used, there was considerable reduction, if not complete disappearance, of lingual morbidity and the facial functional results were constant and satisfactory: there were five patients with House and Brackmann Grade III and one with Grade IV, and their mean percentage of facial mobility was 43.3%.

Selective role of partial XI-VII anastomosis in facial reanimation

OBJECTIVES

Review techniques available for transposition of an alternative motor neuron if end-to-end anastomosis or interposition nerve grafting cannot be accomplished when there has been a complete facial nerve loss. Describe the selective use of a partial spinal accessory-facial nerve anastomosis and highlight cases when this may be a useful alternative. Describe the modifications of decompression of the facial nerve for tension-free anastomosis and the use of the muscle pedicle for repair of cerebrospinal fluid leakage.

STUDY DESIGN

Report of three cases and a review of the literature.

METHODS

Charts were reviewed and indications for the procedure were analyzed. The degree of facial movement was recorded as well as the resolution of any cerebrospinal fluid leak.

RESULTS

The results varied between Class III and Class IV on the House-Brackmann scale following initial complete paralysis. In the two cases in which spinal fluid leakage had occurred before surgery the leakage was resolved. No donor site morbidity was noted.

CONCLUSIONS

The potential of low morbidity associated with the use of the sternocleidomastoid branch, along with the potential for delivering a vascularized muscle pedicle to the temporal bone region, makes selective use of this procedure a valuable addition to the multiple reconstruction options for the paralyzed face.

Intracranial facial nerve neurinoma: surgical strategy of tumor removal and functional reconstruction

BACKGROUND

Three cases with intracranial facial neurinoma underwent tumor removal and facial nerve reconstruction with or without tympanoplasty. Surgical strategy for each case was tailored to: (1) the site of main tumor mass, (2) its extension along the facial nerve, and (3) involvement of the auditory organs.

METHODS

Surgeries adopted in the three cases were: transpetrosal approach with intracranial-intratemporal facial nerve anastomosis, middle fossa and transmastoid approach with intratemporal facial nerve anstomosis and tympanoplasty, and middle fossa and transmastoid approach with intracranial-intratemporal facial nerve anastomosis and tympanoplasty. The greater auricular nerve was used as the nerve graft for all three cases.

RESULTS

In the follow-up period of 8-13 months there was no tumor recurrence; facial function was scored 20/90 in modified May's scoring system in each case, but two are still in the process of functional recovery. One of the two cases who underwent tympanoplasty showed complete recovery of hearing within 1 month, and the other showed worsened hearing, which was not serviceable at 3 months postoperatively.

CONCLUSION

Systematic surgical approach for tumor removal, facial nerve reconstruction, and auditory reconstruction should be considered in cases with intracranial facial neurinoma due to its varied clinical features.

A new technique for hypoglossal-facial nerve repair

Hypoglossal reinnervation of the facial nerve may be required after a proximal facial nerve injury. The classic hypoglossal-facial graft procedure involves transection of the donor hypoglossal nerve, resulting in hemiglottic paralysis that, in association with paralysis of other cranial nerves, may cause speech and swallowing difficulties. Multiple lower cranial nerve palsies in conjunction with facial paralysis, as may occur after procedures such as skull base surgery, contraindicate the use of such techniques. The successful use of XII-VII "interposition jump grafts" without hemiglossal weakness has been described However, a prolonged recovery period and weaker facial reanimation have been seen. In order to attain maximum facial reinnervation while preserving hypoglossal function, we have developed a new technique of XII-VII repair. This method involves mobilization of the intratemporal portion of the facial nerve remnant, achieving a single anastomosis with the hypoglossal nerve, which has been partially incised. This technique has been used in three patients to date, with 6 to 11 months follow-up. In all cases facial tone and symmetry have been restored and voluntary facial expression accomplished. The authors conclude that by employing the techniques described highly satisfactory cosmetic and functional results may be expected, without compromising hypoglossal nerve function.

Neurocutaneous island flaps in upper limb coverage: experience with 44 clinical cases

The vascularity of the cutaneous nerve of the upper limb is closely connected with the vascularity of the skin. Both skin and nerves are vascularized by perforators of the main arteries. Small longitudinal paraneural vessels, in close contact with the cutaneous nerves that they supply, link these perforating arteries. Based on these anatomic findings, 44 cutaneous flaps (so-called neurocutaneous flaps, supplied by the vessels around and inside the cutaneous nerves) were raised. The neurocutaneous flap provided reliable coverage of skin defects in the upper limb. The flap dimensions were as large as 4 x 10 cm. The proximally based flaps were extremely safe, as were the free flaps and the flaps based distally on the dorsal side of the hand. One flap distally based on the medial antebrachial cutaneous nerve of the forearm and three used in thumb reconstruction underwent necrosis. Neurocutaneous island flaps are easy to dissect, they are reliable and versatile, and major vessels like the radial, ulnar, and posterior interosseous arteries are preserved. In the majority of cases, the donor site may be closed primarily and donor site morbidity is minimal.

Management of 1000 vestibular schwannomas (acoustic neuromas): the facial nerve--preservation and restitution of function

OBJECTIVE

Although the rate of reported facial nerve preservation after surgery for vestibular schwannomas continuously increases, facial nerve paresis or paralysis is a frequent postsurgical sequelae of major concern. The major goal of this study was to define criteria for the right indication, timing, and type of therapy for patients with palsies despite anatomic nerve continuity and those with loss of anatomic continuity.

METHODS

One thousand vestibular schwannomas were surgically treated at the Department of Neurosurgery at Nordstadt Hospital from 1978 to 1993. Of 979 cases of complete removal and 21 cases of deliberately partial removal, the facial nerve was anatomically preserved in 929 cases (93%). The rate of preservation is increasing, as is evidenced in the most recent cases, and preservation is supported by special electrophysiological monitoring. The facial nerve was anatomically severed in 60 cases (6%). It was anatomically lost in previous operations that were performed elsewhere in 11 cases (1%). In case of nerve discontinuity (42 cases), immediate nerve reconstruction by one of three available intracranial procedures (within the cerebellopontine angle, intracranial-intratemporal, intracranial-extracranial) was performed in the same surgical setting. In case of loss of the proximal facial nerve stump at the brain stem, early reanimation by combination with the hypoglossal nerve was achieved in most patients within weeks after tumor surgery. In a few patients with anatomic nerve continuity but absence of reinnervation for 10 to 12 months, a hypoglossal-facial combination was applied. All the patients with partial or with complete palsies were treated in a special follow-up program of regular controls and of modulation of physiotherapeutic treatment every 3 to 6 months.

RESULTS

In intracranial nerve reconstruction at the cerebellopontine angle, 61 to 70% of patients regained complete eye closure and an overall result equivalent to House-Brackmann Grade 3. Hypoglossal-facial reanimation led to Grade 3 in 79%. The duration between the onset of paralysis and the reconstructive procedure is decisive for the quality of the outcome. These data are discussed in view of other treatment options and certain parameters influencing outcome.

CONCLUSIONS

This management contains three major principles as follows: 1) preservation of facial nerve continuity in function by the aid of intraoperative monitoring, 2) early nerve reconstruction in case of lost continuity, and 3) scheduled follow-up program for all patients with incomplete or complete palsies.

Management of vestibular schwannomas (acoustic neuromas): auditory and facial nerve function after resection of 120 vestibular schwannomas in patients with neurofibromatosis 2

OBJECTIVE

Vestibular schwannomas (VSs) affect young patients with Neurofibromatosis 2 (NF-2) and cause very serious problems for hearing, facial expression, and brain stem function. Our objective was to determine a therapy concept for the right timing and indication of neurosurgical therapy.

METHODS

In 1000 consecutive VS resections, 120 tumors in 82 patients with NF-2 were surgically treated by the same surgeon (MS) at the Department of Neurosurgery at Nordstadt Hospital from 1978 to 1993. The mean age of the patients was 27.5 years. Sixty tumors were surgically treated in 41 male patients, and 60 tumors were surgically treated in 41 female patients. Bilateral tumor resection was performed in 38 patients (76 operations, after previous partial surgery in 15 cases elsewhere), and unilateral operations were performed in 44 patients, 5 of whom had undergone ipsi- or contralateral surgery that was performed elsewhere. The operative and clinical findings are evaluated and compared with the data of patients without NF-2.

RESULTS

In 105 cases, complete tumor resections were achieved. In 15 cases, deliberate subtotal resections were performed. These were for brain stem decompression in 4 cases and for hearing preservation in the last hearing ear in 11 cases, with successful preservation in 8 of the 11. Pre- and postoperative hearing rates were higher in male than in female patients (70% in male versus 65% in female patients before surgery and 40.5 versus 31%, respectively, after surgery). Hearing was preserved in 29 of 81 ears (36%). The rate of preservation was 24% in cases of large tumors and 57% in cases of small tumors (<30 mm). Twenty-one of 82 patients (26%) were bilaterally deaf before surgery. Twenty-five patients had uni- or bilateral hearing after surgery (i.e., 41 % of those with preoperative hearing or 30.5% of the whole group). Anatomic facial nerve preservation was achieved in 85%. The facial nerve was reconstructed intracranially at the cerebellopontine angle by sural grafting in 17 cases and by hypoglossal-facial reanimation in 5. Two deaths occurred 1 and 3 months postsurgically as a result of malignant tumor growth with brain stem dysfunction and respiratory problems. In summary, for patients with NF-2, the presentation ages are lower, tumor progression is faster, the chances of anatomic and functional nerve preservation are lower, the chances of good outcomes are best when surgery is performed early and when there is good preoperative hearing function, and the danger of sudden hearing loss is higher. The chances and danger often differ from side to side among individual patients.

CONCLUSION

The indication and the timing of tumor resections are in some respects different from normal VS handling and are dependent on the tumor extension and related necessity of brain stem decompression and on the auditory function. As an optimal goal, completeness of resection with functional cochlear nerve preservation is formulated, and as an acceptable compromise, subtotal microsurgical resection with functional cochlear nerve preservation in the last hearing ear is suggested.

Hypoglossal-facial nerve side-to-end anastomosis for preservation of hypoglossal function: results of delayed treatment with a new technique

This report describes a new surgical technique to improve the results of conventional hypoglossal-facial nerve anastomosis that does not necessitate the use of nerve grafts or hemihypoglossal nerve splitting. Using this technique, the mastoid process is partially resected to open the stylomastoid foramen and the descending portion of the facial nerve in the mastoid cavity is exposed by drilling to the level of the external genu and then sectioning its most proximal portion. The hypoglossal nerve beneath the internal jugular vein is exposed at the level of the axis and dissected as proximally as possible. One-half of the hypoglossal nerve is transected: use of less than one-half of the hypoglossal nerve is adequate for approximation to the distal stump of the atrophic facial nerve. The nerve endings, the proximally cut end of the hypoglossal nerve, and the distal stump of the facial nerve are approximated and anastomosed without tension. This technique was used in four patients with long-standing facial paralysis (greater than 24 months), and it provided satisfactory facial reanimation, with no evidence of hemitongue atrophy or dysfunction. Because it completely preserves glossal function, the hemihypoglossal-facial nerve anastomosis described here constitutes a successful approach in patients with long-standing facial paralysis who do not wish to have tongue function compromised.

Hypoglossal-facial nerve side-to-end anastomosis for preservation of hypoglossal function: results of delayed treatment with a new technique

This report describes a new surgical technique to improve the results of conventional hypoglossal-facial nerve anastomosis that does not necessitate the use of nerve grafts or hemihypoglossal nerve splitting.

Using this technique, the mastoid process is partially resected to open the stylomastoid foramen and the descending portion of the facial nerve in the mastoid cavity is exposed by drilling to the level of the external genu and then sectioning its most proximal portion. The hypoglossal nerve beneath the internal jugular vein is exposed at the level of the axis and dissected as proximally as possible. One-half of the hypoglossal nerve is transected: use of less than one-half of the hypoglossal nerve is adequate for approximation to the distal stump of the atrophic facial nerve. The nerve endings, the proximally cut end of the hypoglossal nerve, and the distal stump of the facial nerve are approximated and anastomosed without tension. This technique was used in four patients with long-standing facial paralysis (greater than 24 months), and it provided satisfactory facial reanimation, with no evidence of hemitongue atrophy or dysfunction.

Because it completely preserves glossal function, the hemihypoglossal-facial nerve anastomosis described here constitutes a successful approach in patients with long-standing facial paralysis who do not wish to have tongue function compromised.