[Biomechanical study of a ventral stand-alone cage for the lumbar spine with and without additional posterior fixation]. / Biomechanische Studie über einen ventralen "stand alone cage" für die lumbale Wirbelsäule mit oder ohne zusätzliche dorsale Stabilisation.

AIM: Biomechanical study to examine the stability of a stand-alone cage (SAC; Topaz, Ulrich Medizintechnik, Ulm) incorporating integrated anterior fixation with and without additional posterior fixation. METHOD: Six human spinal specimens (L4/5) were loaded in a spine tester in the three main motion planes in the following states: (a) intact, (b) defect (nucleotomy), (c) SAC, (d) SAC+internal fixator (IF), and (e) SAC+translaminar facet screws (TFS). Facet joint translation (FJT) and range of motion (ROM) were measured and used to evaluate the stability of the tested states. RESULTS: The SAC stabilized the segment in comparison to the intact (a) and defect-containing (b) segments. The most rigid fixation was found for SAC+IF compared with the other states (a, b, c, e). The ROM and FJT of the SAC with the additional IF (d) showed a significant higher stability in all three motion planes. All differences in ROM and FJT between the tested states were statistically significant (p<0.05) except for the FJT SAC and SAC+TFS. CONCLUSION: The ventral Topaz SAC is a stable implant for the lumbar spine. Additional dorsal stabilization is an option to increase the stability.

Vertebral body replacement system Synex in unstable burst fractures of the thoracic and lumbar spine.

A prospective longitudinal study was performed to evaluate the vertebral body replacement system Synex associated with posterior fixation in unstable burst fractures of the lumbar and thoracic spine. Within 24 months, we treated 28 patients (average age, 41 years; range, 22-64 years; 14 women, 14 men) with acute unstable burst fractures without osteoporosis of the thoracolumbar region (n=16) and the thoracic (n=3) as well as the lumbar (n=9) spine in two stages (primary dorsal transpedicular stabilization and secondary vertebral body replacement). The complications were analyzed and the postoperative follow-up result was evaluated regarding stability, bone fusion, correction loss, pain and neurological status. One patient showed a transient irritation of the lumbosacral plexus and one patient had a superficial wound infection (complication rate, 7.1%). At the follow-up examination (mean follow-up, 13 months) only in two cases a minimal loss of correction (<5°) was measured. Radiologically, 27 patients showed secure bone fusions and all patients had stability of the osteosynthesis. Most of the patients stated no or just slight pain at follow-up. Only two patients with pain to a medium degree had to take painkillers. The vertebral body replacement system Synex seems to be a good alternative for vertebral body replacement in unstable burst fractures of the thoracic and lumbar spine since at present follow-up it shows a high rate of bone fusion and minimal loss of correction.

[Anterior lumbar interbody fusion (ALIF) using a cage with stabilization]. / Anteriore lumbale interkorporelle Fusion (ALIF) mit einem stabilisierenden Cage.

AIM: The authors have conducted a prospective observational study to evaluate the clinical and radiological outcome and complications associated with anterior lumbar interbody fusion (ALIF) using a cage with stabilization. MATERIALS AND METHODS: Eighteen patients ranged in age from 36 to 77 years (mean 53 years) who had undergone ALIF were prospectively evaluated. Clinical outcome was graded using a modified Prolo scale (economic, pain, medication) and radiological outcome was recorded (X-rays). RESULTS: Based on Prolo scale scores, excellent or good outcomes were achieved in 61 % of these patients (75 % mono-segmental degenerative disc disease: n = 8; and 50 % after failed-back surgery syndrome: n = 10). The mean follow-up was 14 months (from 12 to 18 months) after surgery. Postoperative X-rays demonstrated solid arthrodesis for 12 (66 %) of the 18 patients. Complications requiring repeated surgery included one case of postoperative peritonitis without infection of the cage. We found one deep-vein thrombosis. There were four cases with postoperative meralgia paresthetica. On routine follow-up radiography one cage was found to be dislocated (2 mm) and in one case we found two broken screws. CONCLUSION: The ALIF cage with stabilization is one possible therapy option for treatment of mono-segmental degenerative disc disease and failed-back surgery after unsuccessful conservative therapy. However, the clinical results should be interpreted with caution.

[Possibilities for cost reduction of implants in spinal surgery]. / Möglichkeiten zur kostenoptimierten Implantatauswahl in der Wirbelsäulenchirurgie.

OBJECTIVE: To evaluate the possibilities for cost reduction in spinal surgery by analysing implant costs and the efficiency of each type of implant. MATERIALS AND METHODS: The costs of spinal implant methods, as well as Halo-vest for craniocervical, cervical, thoracic, lumbar spine are summarised according to an analysis of price lists from 2001 and 2002. The different methods were additionally evaluated with regard to the scientifically-based treatment efficiency. All prices above 100 euro were rounded up to the closest 50 euro. For the implants, a literature research was performed. The scientific papers were divided into groups according to their level of evidence (I a -IV), and then further subdivided into comparable and non-comparable categories. RESULTS: Craniocervical: Halo-vest 1,700-2,500 euro, odontoidscrew 100-250 euro, plate 1,300 euro, wire 20-250 euro; plate-wire-, rod-wire- or rod-screw systems 400-1,800 euro, clamps 1,200 euro, Cervical: placeholder 20-500 euro, vertebral body replacement 400-1,300 euro, plate 75-450 euro; rod- or plate-screw systems 900-1,700 euro; Thoracic/lumbar: plate/rod-systems 1,000-2,800 euro, vertebral body replacement 500-1,300 euro, internal fixateur 800-2,500 euro, cages 600-1,500 euro. For none of the implant methods were comparable scientific clinical publications found with a high levels of evidence (I a-I b). CONCLUSIONS: Costs can be reduced through a more thorough investigation and corresponding choice of implant method. The cost-benefit analysis of new spinal implants must be considered more with regard to the evidence-based spinal surgery. In order to sufficiently evaluate the different treatment methods, future multicenter controlled comparable studies and meta-analyses must be undertaken.

[Vertebral body replacement system Synex in unstable burst fractures of the thoracic and lumbar spine--a retrospective study with 30 patients]. / Wirbelkörperersatzsystem Synex bei instabilen Berstungsfrakturen der Brust- und Lendenwirbelsäule--eine retrospektive Studie bei 30 Patienten.

OBJECTIVES: Retrospective analysis of the vertebral body replacement system Synex in unstable burst fractures of the lumbar and thoracic spine. PATIENTS AND METHODS: Within 22 months, we treated 30 patients (average age: 45, range: 20- 73 years, 16 females, 14 males) with unstable burst fractures of the thoracolumbar (n=20) and the thoracic (n=2) as well as lumbar (n=8) spine in two stages (primary dorsal transpedicular stabilization with fixateur interne under navigator guidance and intraoperative CT and secondary vertebral body replacement using the Synex). In three patients with osteoporosis we performed additional ventrolateral plate fixation. The complications of the operation were analyzed and the postoperative follow-up results were evaluated regarding stability, bony fusion, loss of correction, pain and neurological status. RESULTS: There was one postoperative instability, two transient neurological deteriorations and one case with seroma of the pleura. At follow-up examination (mean follow-up 14 months) an average loss of correction of 1.6 degrees was measured. Without osteoporosis a loss of correction of 5 degrees was observed in one case. In four osteoporotic patients without ventrolateral stabilization a mean loss of correction of 10 degrees was present. At the follow-up examinations a bony fusion was documented in 27 and stability in all patients. Most of the patients stated either no or only minor pains at follow-up. Only two patients with pain of medium degree had to take pain medication. CONCLUSIONS: The vertebral body replacement system Synex is a good technical possibility for a vertebral body replacement in unstable burst fractures of the thoracic and lumbar spine. With osteoporosis an additional anterior stabilization is to be recommended.

Surgery for upper cervical spine instabilities in children.

BACKGROUND: Due to the paucity of existing data with regard to surgical fusion of upper cervical spine instabilities in the paediatric population, we feel encouraged to report the results of our own series to provide additional information to the available body of literature. METHODS: Since 1991 N = 11 children underwent a total of N = 13 surgical procedures for N = 8 posttraumatic, N = 2 congenital and N = 1 postinfectious instabilities at a mean age of 10 years (range: 3-16 years). Transoral odontectomies, ventral odontoid screw-fixations, dorsal wiring or -clamping and transarticular screw-fixations were performed for stabilization and iliac crest bone graft used for fusion. Pain scores, neurological status and radiological results were documented at regular intervals (mean follow-up: 25.4 months). RESULTS: Stable fusion was achieved in all patients as documented on flexion/extension films and tomographies. At the latest follow-up N = 2 patients had improved and N = 9 were equal to their preoperative neurological status. Pain scores were improved in N = 9 patients. N = 2 children developed "bystander-fusion" after C0/2 wiring. N = 3 peri-operative complications occurred as transient neurological deteriorations. In one case this resulted from the resection of a lower brainstem tumour prior to the stabilization procedure. One was attributed to sublaminar wiring in the case of an os odontoideum and one occurred due to slippage of the halo orthosis after transoral odontectomy before definitive dorsal stabilization was carried out. INTERPRETATION: In accordance with the recent literature, we argue for the application of modern screw fixations and treatment algorithms as established for adults in upper cervical spine instabilities of older children. Techniques and indications remain problematic for those younger than 6 years and may have to be individualized in congenital instabilities.

Tumour surgery of the upper cervical spine--a retrospective study of 13 cases.

A series of tumour cases of the upper cervical spine who we had treated was analysed retrospectively with respect to surgical complications, quality of life and survival, 13 patients (mean age 56 years, metastases 6, plasmocytomas 3, chordomas 2, histiocytosis 1, aneurysmal bone cyst 1) with tumours of the upper cervical spine (C2 n = 7, C2 and C3 n = 4, C3 n = 2) were treated during an 8-year period. A total of 16 operations were carried out with ten one-step procedures and three two step-procedures. Eight extra-oral, one transoral, three dorsal and, in one case, a combined dorsal and extra-oral tumour removal were performed. Four dorsal stabilisation's, four ventral platings and two combined ventral platings plus dorsal fixations and eight vertebral body replacements were carried out. The neurological status and the quality of life were analysed preoperatively and during the follow-up examinations. Flexionextension radiographs were taken during follow-up. There was no operative mortality. The transient morbidity was 8%. The operative intervention significantly improved the quality of life in all patients during the follow-up visits (mean: 20 months). No instability was seen. The average survival time of all patients was 23 months. Six patients died following the operation after a mean time of 28 (4-64) months. Tumour removal in the upper cervical spine using individually modified surgical strategies based on an approach combining tumour location, stabilisation and vertebral body replacement significantly increases the time of survival and quality of life with an acceptable surgical risk for complications.

A review of halo vest treatment of upper cervical spine injuries.

Thirty-five relevant studies involving in total 682 patients with 709 different types of injuries were evaluated in a review to determine the outcomes after immobilisation in a halo vest for various injuries to the upper cervical spine between 1962 and 1998. Studies were analysed according to the type of injury pattern and in terms of the treatment outcomes following primary treatment with a halo vest. The following types of injuries were evaluated: odontoid fractures (n = 420), hangman's fractures (n = 172), other axis fractures (n = 75), Jefferson fractures (n = 26), C1 arch fractures (n = 9), atlantooccipital (n = 2) and atlantoaxial dislocations (n = 5). The ligamentary atlantooccipital dislocations never healed. All isolated Cl ring fractures healed completely. The isolated C1 arch fractures healed in 83% of the cases. The ligamentary atlantoaxial dislocations had a 60% rate of healing. Healing was noted in all isolated odontoid type I fractures, 85% of the isolated odontoid type II fractures, and 67% of the odontoid type II fractures with combined injuries. The isolated odontoid type III fractures had a 97% healing rate. The non-classifiable odontoid fractures had a healing rate of 85%. The stable C2 arch fractures (hangman's fracture) healed consistently in 99%, and 90% success was found for other C2 fractures. A halo vest can be recommended for patients with isolated Jefferson fractures, hangman's fractures, odontoid type III and type II fractures, with a low dislocation rate. The results of treatment with a halo vest were unsatisfactory with regard to combined injuries with an odontoid type II fracture. An overall healing rate of 86%, however, allows one to conclude that this treatment continues to be a good alternative to operative stabilisation of bone injuries to the upper cervical spine.

Differential treatment in acute upper cervical spine injuries: a critical review of a single-institution series.

BACKGROUND: A single-institution series of injuries of the upper cervical spine are analyzed retrospectively and the literature relevant to the topic is reviewed. METHODS: Seventy patients (34 female, 36 male, mean age 47 years) were admitted during a 5-year period for injuries of the upper cervical spine. Sixty-five were followed for a mean time of 18 months. Three isolated ligamentous instabilities, 6 isolated C1 fractures, 3 complex C2 fractures, 10 combined C1/C2, and 48 C2 fractures (17 hangman's, 31 odontoid) were diagnosed. Twenty-nine patients were treated conservatively and for 41 patients surgery was the primary treatment. Twenty-three ventral odontoid screw fixations, 8 ventral platings and 10 dorsal stabilizations were performed. Stability was evaluated using flexion-extension radiography. Pain levels and neurological outcome were assessed. RESULTS: Operative mortality and neurological morbidity were 0%. Two wound infections and 3 instabilities (17%) in odontoid Type II fractures primarily treated with ventral odontoid screw fixation needed dorsal restabilization. During follow-up examinations the neurological status of three patients was improved. In 62 patients preoperative status was attained. Six patients evaluated their pain as severe, two as disabling. CONCLUSIONS: Candidates for surgery as the primary treatment include those with isolated ligamentous instabilities, Type III hangman's fractures and Type II odontoid fractures with dislocation more than 5 mm. In combined C1/C2 fractures the axis fracture dictates the treatment strategy. Patients who undergo dorsal procedures and have involvement of C1 have a greater chance of developing persistent pain.

[Tumor surgery of the upper cervical spine]. / Tumorchirurgie an der oberen Halswirbelsäule.

Our own series of tumors of the upper cervical spine was analyzed retrospectively. The standard treatment strategies were reevaluated. A total of nine patients (mean age 61 years, metastasis 4, plasmocytoma 3, chordoma 1, histiocytosis 1) were treated between 1/92 and 2/99. A total of 12 operations were carried out. One-step procedures (6): Three extraoral, one transoral, one dorsal and in one case combined dorsal and extraoral tumor removal were performed. Three dorsal occipitocervical or atlantoaxial stabilizations, one ventral plating and two combined ventral plating plus dorsal three-point fixations, and four vertebral body replacements were carried out. Two-step procedures (3): three extraoral tumor removals with ventral plating plus dorsal three-point fixation, in combination with vertebral body replacement in two cases. The neurological status and the quality of life (Karnofsky performance status, pain levels) were analyzed preoperatively and at the follow-up outpatient examinations (mean follow-up: 18 months). Flexion-extension radiographs were performed at the follow-up. There was no operative mortality. The transient morbidity was 11%. The operative intervention improved the quality of life in all patients. Three patients died within 27 months of operation. Tumor resection at the upper cervical spine using individually modified surgical strategies over an approach corresponding to the tumor location, stabilization and vertebral body replacement increases significantly the time of survival and quality of life with an acceptable surgical risk for complications.

Platelet-derived growth factor (PDGF-AB) like immune reactivity in serum and in cerebral spinal fluid following experimental subarachnoid haemorrhage in dogs.

The aim of this study was to evaluate the following questions: Can the platelet-derived growth factor (PDGF-AB) be identified in the serum and cerebro spinal fluid (CSF) of dogs? Is there an increase in the concentration of PDGF-AB following experimental subarachnoid haemorrhage (SAH)? Is the increase in concentration related to the angiographic cerebral vasospasm of the basilar artery. The "double haemorrhage" model was applied in seven dogs to produce experimental SAH with determination of angiographic vasospasm in the basilar artery. Blood and CSF samples were taken on the first, third and eighth days. The analyses were performed with an ELISA human PDGF-AB antibody kit (quantikine human PDGF-AB, R&D Systems, Minneapolis, USA). The average PDGF-AB base value in the serum on the day before the SAH was 410.77 +/- 177.56 pg/ml, in the CSF it was 6.43 +/- 3.19 pg/ml. There was a significant (p = 0.05) increase in the concentration of PDGF-AB (third day 717.35 pg/ml, eighth day 918.07 pg/ml) in the serum of all animals. No significant increase was found in the CSF samples of any animal. In summary, a PDGF-AB like immune reactivity was found in the serum of dogs with the human PDGF-AB ELISA kit and the concentration of PDGF-AB in the serum increased after experimental SAH but not in CSF, but there was no relationship between the increase in PDGF-AB serum concentration and angiographic vasospasm.

Corrosion on an internal spinal fixator system.

STUDY DESIGN: Thirteen spinal fixators with 26 stabilization bridges and 52 pedicle screws and a mean length of implantation of 10 months were prospectively examined for corrosion. OBJECTIVES: To determine the type of corrosion and the correlation between the construction of the spinal fixator and the type of corrosion. SUMMARY OF BACKGROUND DATA: Evidence of fretting and crevice corrosion is seen in many stainless steel implants in retrieval studies. Such reactions have not been described in the literature on spinal fixator systems. METHODS: Macroscopic and microscopic alterations in the adjacent tissue were examined, and the corrosive alterations were documented photographically using stereoscopic optical light microscopy. The chemical composition of the implants was determined spectrographically. Microradiography and x-ray fluorescence analysis of the soft tissue were performed. RESULTS: At surgery, tissue discoloration was found in four cases. Histologic examination showed extensive fibrosis, foreign body reaction and inflammation associated with a small number of metal particles, indicating metallosis in five cases. Corresponding particles were detected by microradiography. Corrosion was found on 13 telescopic rods and on two pedicle screws. The alterations on the telescopic rods could be interpreted as crevice corrosion and the alterations in the pedicle screws as fretting corrosion. The two monobloc fixator bridges did not show signs of corrosion. In these implants, the neighboring tissue was macroscopically inconspicuous, and histologic examination showed minimal fibrosis or presence of metal particles. Spectrographic examination of the spinal fixators showed no structural imperfection. CONCLUSIONS: The construction constraints of a spinal fixator make it prone to corrosion. New spinal implants should be examined not only in vitro but also in vivo to ascertain whether corrosion and adjacent tissue reaction occur. Corrosion is one reason to explant the internal fixation system after fusion of the spinal fracture.

Petroclival meningiomas: is radical resection always the best option?

BACKGROUND: The surgical management of petroclival meningiomas is, despite the invaluable technical achievements in the past decade, still burdened by a high operative morbidity. It seems doubtful whether radical surgical removal should always be the primary goal in those lesions as advocated until very recently. METHODS: A series was critically analysed and the literature discussed to elucidate criteria for a different attitude. Between 1990 and 1995 a total of 19 patients harbouring petroclival meningiomas were operated on. The following approaches were used: petrosal (n = 13), retrosigmoidal (n = 5), and subtemporal (n = 1). Thirteen lesions were removed completely and six incompletely as assessed by postoperative MRI. RESULTS: No recurrence or regrowth could be detected on MRI after a mean follow up of 18 months. Surgical mortality occurred in one patient (5%) and there was early postoperative dysfunction in 56%. At the time of follow up major permanent operative morbidity was present in two patients (11%). CONCLUSIONS: In accord with recent literature subtotal resection of petroclival meningiomas should be contemplated in a subset of patients (with invasion of brain stem or cavernous sinus) to reduce the incidence of disabling deficits. Surgery should not be delayed in younger patients because surgical morbidity relates positively with tumour size.

Diagnosis and treatment of frontobasal skull fractures.

During a five-year-period (January 1990 to December 1994) a total of 67 patients were operated on for frontobasal skull fractures. The indication for surgical treatment was based on the evidence of fractures encroaching paranasal sinuses or the cribriform plate on high-resolution axial or coronal CT scans. The following clinical signs indicating frontobasal trauma were observed: 25 patients (37%) showed rhinoliquorrhea, 14 (21%) had raccoon's eyes, and 2 (3%) had meningitis. Distinct dura laceration was observed intraoperatively in 64 of 67 patients (96%). In our experience, high resolution CT has proven to be a sensitive diagnostic tool for frontobasal skull fractures. With respect to the high coincidence of fractures and dura lacerations, the indication for surgical treatment based on CT findings seems to be justified.

A flexible metal ventricular catheter for treatment of complicated and protracted infections of the cerebrospinal fluid spaces: preliminary experiences.

In the management of shunt infection, the use of ventricular catheters made of silicone rubber for the temporary external drainage of cerebrospinal fluid (CSF) is general practice. However, the eradication of the primary source of infection may be hindered by the affinity of bacteria to silicone-based material. Compared to silicone catheters, a metal drainage device for temporary ventriculostomy appears to offer more favourable conditions for successful eradication of the infection. Since metal needles cannot be implanted permanently and since their screw-type fixation precludes attachment to the skulls of infants or small children, we developed a flexible metal catheter. This catheter was used exclusively for the treatment of particularly serious or chronic infections of the CSF spaces. The catheter is made of implantation steel and consists of a corrugated tube that renders it flexible. Cerebrospinal fluid drains into a receptable bulb at the tip of the tube. Tubing of other materials may be connected to the end of the metal catheter for either external or internal drainage. It was implanted as a temporary and later permanent CSF drainage in 7 male patients aged from 4 to 60 years, who suffered from chronic, recurrent ventriculitis (n = 5) with an average of 7 previous surgical revisions, as well as from complex infections (n = 2; basal tuberculous meningitis, brain abscess). The infections were successfully eliminated in 6 patients. In the remaining patient, the metal catheter for external ventriculostomy had to be removed after 4 days due a leakage of CSF; it was replaced by a silicone catheter and later on by a needle drainage. Other complications, such as secondary infection or intracerebral haemorrhage, did not occur. The average duration of external CSF drainage via the flexible metal catheter was 27 days (range 4-50 days). In 4 patients, the CSF drainage was converted to a permanent ventriculoperitoneal shunt using a new flexible metal catheter. At the time of post-operative follow-up examination (average = 34 weeks), all shunts were functioning and there was no evidence of infection. In cases of especially complicated and protracted CSF infections, the flexible metal ventricular catheter is a promising device for treatment.

[Vertebral body replacement with a rib segment block in transthoracic intervention]. / Wirbelkörperersatz mit einem Rippensegmentblock beim transthorakalen Eingriff.

The aim of this clinical report is to describe the outcome of 7 patients regarding the efficiency of a vertebral body replacement with rib bone for destructive lesions in the thoracic spine. In these patients, an autologous bone block shaped from four rib segments, was used as a vertebral body replacement. In order to compose the bone block, the ribs were fused by means of one or two commercialized titanium screws. In a retrospective study the following parameters were analysed: neurological status, rate of bony fusion, primary correction gain, secondary correction loss. Mean time of follow-up was eleven months (range 6-20). Neurological improvement was found in 83.3% of patients treated with ventral decompression. Immediate postoperative gain of correction was 9.4 angle degrees, secondary loss of correction was 11.4 angle degrees, the latter resulting from the impression of the rib segments into the adjacent vertebrae. Radiological bony fusion of the rib implants could be observed in all cases. To avoid a secondary loss of correction, ventral fusion using an osteosynthesis plate and, in singular cases, the dorsal implantation of a fixateur interne is advantageous. An additional advantage of this new method is that autologous bone harvesting is accomplished during the surgical approach, rendering a separate approach for this purpose superfluous (thus shortening operation time, reducing morbidity and operative complications). We conclude from our results that the composed rib block is an attractive alternative vertebral body replacement which provides sufficient stability and osteogenic capacity.

[Primary leptomeningeal sarcomatosis in a 26-year-old patient]. / Primäre Leptomeninxsarkomatose bei einem 26 Jahre alten Patienten.

Primary malignant mesenchymal tumours were seen in 2.4 per cent of all autopsy cases with primary CNS-tumours. Primary leptomeningeal sarcomatosis is rare in this group of tumours. We discuss the rare disease on the basis of the case history of a 26-year-old patient.

[Innervation anomalies--mechanism of adaptation or embryonal malformation?]. / Innervationsanomalien--Anpassungsmechanismus oder embryonale Fehlentwicklung?

After injuries innervationanomalies are observest. Are these anomalies mechanismen of adaption or an embryological malformation, is a still mansverst question. This paper tries some contributions to the answer. The use of modern muscleenzymhistochemistry in connection of histological findings of nerves in certain levels gives assertions on anomalies of innervation and mechanisms of reinnervation. After 14, 28, 56 and 112 days tissues of nerves and muscle from 66 female WISTAR-rats were investigated after various lesions. We have found in 15 not operated rats that the so called typegrouping can be a expression of reparation process after microlesions of nerve and muscle. We interpreted the anomalies as an expression of a reaction of adaption. The innervationanomalies succeeded in the fore and behind extremities of the rate indirectly. Above all embryological malformations can explain some anomalies of innervation on the fore extremities. We conclude from our results that communication among nerves and nerve bundles were developed or activated. These mechanism seems to be effective only about a short distance. We did not find a MARTIN-GRUBER-anostomosis. The findings of reinnervation of the musculature were attributed to cross-innervation, collateral and orthotope reinnervation. Generally the innervationanomalies are an expression of plasticity of the peripheral nervous system in all periods of life. In the first place we interpreted this phenomenous as adaption of nerves after injury and in the second place as embryological malformation.