Anatomic study of the superficial sural artery and its implication in the neurocutaneous vascularized sural nerve free flap

Combined extended nerve and soft tissue defects of the upper extremity require nerve reconstruction and adequate soft tissue coverage. This study focuses on the reliability of the free vascularized sural nerve graft combined with a fasciocutaneous posterior calf flap within this indication. An anatomical study was performed on 26 cadaveric lower extremities that had been Thiel fixated and color silicone injected. Dissection of the fasciocutaneous posterior calf flap involved the medial sural nerve and superficial sural artery (SSA) with its septocutaneous perforators, extended laterally to include the lateral cutaneous branch of the sural nerve and continued to the popliteal origin of the vascular pedicle and the nerves. The vessel and nerves diameter were measured with an eyepiece reticle at 4.5× magnification. Length and diameter of the nerves and vessels were carefully assessed and reported in the dissection book. A total of 26 flaps were dissected. The SSA originated from the medial sural artery (13 cases), the popliteal artery (12 cases), or the lateral sural artery (one case). The average size of the SSA was 1.4 ± 0.4 mm. The mean pedicle length before the artery joined the sural nerve was 4.5 ± 1.9 cm. A comitant vein was present in 21 cases with an average diameter of 2.0 ± 0.8 mm, in 5 cases a separate vein needed to be dissected with an average diameter of 3.5 ± 0.4 mm. The mean medial vascularized sural nerve length was 21.2 ± 8.9 cm. Because of inclusion of the vascularized part of the lateral branch of the sural nerve (mean length of 16.7 ± 4.8 cm), a total of 35.0 ± 9.6 cm mean length of vascularized nerve could be gained from each extremity. The free vascularized sural nerve graft combined with a fasciocutaneous posterior calf flap pedicled on the SSA offers a reliable solution for complex tissue and nerve defect. Clin. Anat. 2012. © 2012 Wiley Periodicals, Inc.

[Endoscopic decompression of the ulnar nerve in the cubital tunnel syndrome: about 55 patients]

Sulcus ulnaris syndrome is the second most common neurocompression syndrome in the upper limb after carpal tunnel syndrome. Its severity can be appreciated by the Dellon Classification. We present our experience and results after endoscopic decompression.

Retrograde cochlear implantation in postmeningitic basal turn ossification

Postmeningitic basal turn ossification is a challenge for successful cochlear implantation despite the availability of sophisticated implants and advanced drill-out procedures. A less complex concept consisting of a cochleostomy near the apex with retrograde array insertion is evaluated clinically and experimentally with emphasis on imaging of intracochlear array morphology.

A mouse model of Schwartz-Jampel syndrome reveals myelinating Schwann cell dysfunction with persistent axonal depolarization in vitro and distal peripheral nerve hyperexcitability when perlecan is lacking

Congenital peripheral nerve hyperexcitability (PNH) is usually associated with impaired function of voltage-gated K(+) channels (VGKCs) in neuromyotonia and demyelination in peripheral neuropathies. Schwartz-Jampel syndrome (SJS) is a form of PNH that is due to hypomorphic mutations of perlecan, the major proteoglycan of basement membranes. Schwann cell basement membrane and its cell receptors are critical for the myelination and organization of the nodes of Ranvier. We therefore studied a mouse model of SJS to determine whether a role for perlecan in these functions could account for PNH when perlecan is lacking. We revealed a role for perlecan in the longitudinal elongation and organization of myelinating Schwann cells because perlecan-deficient mice had shorter internodes, more numerous Schmidt-Lanterman incisures, and increased amounts of internodal fast VGKCs. Perlecan-deficient mice did not display demyelination events along the nerve trunk but developed dysmyelination of the preterminal segment associated with denervation processes at the neuromuscular junction. Investigating the excitability properties of the peripheral nerve suggested a persistent axonal depolarization during nerve firing in vitro, most likely due to defective K(+) homeostasis, and excluded the nerve trunk as the original site for PNH. Altogether, our data shed light on perlecan function by revealing critical roles in Schwann cell physiology and suggest that PNH in SJS originates distally from synergistic actions of peripheral nerve and neuromuscular junction changes.

Sciatic-femoral nerve block with bupivacaine in goats undergoing elective stifle arthrotomy

The aim of this study was to describe the sciatic-femoral nerve block (SFNB) in goats and to evaluate the peri-operative analgesia when the goats underwent stifle arthrotomy. The animals were randomly assigned to one of four treatment groups: groups 0.25, 0.5 and 0.75 received 0.25%, 0.5% and 0.75% of bupivacaine, respectively, while group C (control group) received 0.9% NaCl. In all groups, the volume administered was 0.2 mL/kg. Intra-operatively, the proportion of animals receiving rescue propofol was significantly lower in groups 0.5 and 0.75, compared to group C. Post-operatively, the visual analogue scale (VAS) and total pain score were significantly higher in group C than in the other groups. Group 0.75 had the highest percentage of animals showing motor blockade. SFNB performed with bupivacaine resulted in better intra- and post-operative analgesia than SFNB performed with saline. Compared to the other concentrations, 0.5% bupivacaine resulted in satisfactory analgesia with acceptable side effects.

Quantitative assessment of physiological and behavioural parameters in healthy dairy cows evoked by transcutaneous electrical nerve stimulation of the udder

The pain and distress associated with transcutaneous electrical nerve stimulation (TENS) of the udder was evaluated by treating 20 healthy dairy cows with an electrical udder stimulator. This generated a sequence of pulses (frequency: 160+/-10% impulses per second, duration 250 mus) and provided voltage ranges from 0 to 10 volts (+/-10%). Trials took place on three consecutive days, twice daily after morning and evening milking. Daily sessions were divided into two periods: (1) control (sham treatment) and (2) treatment (real treatment). Physiological (heart rate, respiratory rate, and plasma cortisol concentration) as well as ethological parameters (kicking, weight shifting, and looking backwards to udder) were defined as pain-indicating parameters and observed. Evaluation of data showed that only one parameter (kicking) was significantly increased during real treatment compared to sham treatment. It is concluded that the TENS therapy tested in this study can evoke changes in behaviour (increased kicking) consistent with an experience of pain in some cows.

A self-developed and constructed robot for minimally invasive cochlear implantation

Conclusion: A robot built specifically for stereotactic cochlear implantation provides equal or better accuracy levels together with a better integration into a clinical environment, when compared to existing approaches based on industrial robots. Objectives: To evaluate the technical accuracy of a robotic system developed specifically for lateral skull base surgery in an experimental setup reflecting the intended clinical application. The invasiveness of cochlear electrode implantation procedures may be reduced by replacing the traditional mastoidectomy with a small tunnel slightly larger in diameter than the electrode itself. Methods: The end-to-end accuracy of the robot system and associated image-guided procedure was evaluated on 15 temporal bones of whole head cadaver specimens. The main components of the procedure were as follows: reference screw placement, cone beam CT scan, computer-aided planning, pair-point matching of the surgical plan, robotic drilling of the direct access tunnel, and post-operative cone beam CT scan and accuracy assessment. Results: The mean accuracy at the target point (round window) was 0.56 ± 41 mm with an angular misalignment of 0.88 ± 0.41°. The procedural time of the registration process through the completion of the drilling procedure was 25 ± 11 min. The robot was fully operational in a clinical environment.

Clinical course of a malignant peripheral nerve sheath tumor in a Siberian tiger (Panthera tigris altaica)

A 14-year-old male Siberian tiger (Panthera tigris altaica) was admitted with an ulcerating mass on the right thoracic wall. Radiographic and computed tomographic evaluation indicated 2 isolated cutaneous masses without any signs of metastasis. Histology of a Tru-Cut biopsy revealed an anaplastic sarcoma with giant cells. Both tumors were resected with appropriate normal tissue margins. The size of the defect did not allow primary closure of the wound; therefore, a mesh expansion technique was attempted. Three months later, the tiger had to be euthanized due to extensive metastasis to the lungs. Histomorphological features and immunohistochemical results confirmed the diagnosis of malignant peripheral nerve sheath tumor. In contrast to domestic animal experience, the tumor had spread extensively to the lungs without local reccurrence in a short period of time. Correct diagnosis requires various immunohistochemical evaluations of the tumor tissue.

Plexiform hybrid granular cell tumor/perineurioma: a novel variant of benign peripheral nerve sheath tumor with divergent differentiation

The descriptive term hybrid peripheral nerve sheath tumor refers to any neoplasm of the neurilemmal apparatus composed of more than one pathologically defined tumoral equivalent derived from its constituent cells. Within this uncommon nosological category, participation of granular cell tumor - a neoplasm of modified Schwann cells - has been reported only exceptionally. We describe a hitherto not documented variant composed of an organoid mixture of granular cell tumor and perineurioma with plexiform growth. A solitary subcutaneous nodule of 1.5 cm diameter was excised from the right ring finger of a 19-year-old female with no antecedents of neurofibromatosis or relevant trauma. Histology revealed a monotonous, yet cytologically dimorphic proliferation of classical granular cells intermingled with flattened, inconspicuous perineurial cells. Immunohistochemical double labeling detected expression of S100 protein in the former and of EMA and GLUT-1 in the latter. While the respective staining patterns for S100 protein and EMA or GLUT-1 tended to be mutually exclusive, a minority of cells exhibited transitional granular cell/perineurial immunophenotype. Electron microscopy permitted direct visualization of a plethora of lysosomes in the granular cell moiety, and of pinocytotic vesicles and tight junctions in perineurial cells. Intratumoral axons were not detected. Expanding intraneurally, the lesion showed discrete encapsulation by the local perineurium, and resulted in plexiform growth. The MIB-1 labeling index averaged 1%. We interpret our findings as supporting evidence for the dual cell lineage to have arisen through metaplasia, with the tumor's dynamics probably having been driven by the granular cell component.

Suspected paradoxical nerve root signature in a dog with right-sided intervertebral lumbar disk extrusion: a case report

A 7 year old male mongrel dog was presented with a 3 weeks history of gait disturbance in the pelvic limbs more pronounced on the left side associated with pain in the lumbar spine. At presentation neurologic deficits consisted of mild bilateral proprioceptive deficits and nerve root signature in the left pelvic limb. A large intervertebral disc herniation L3-L4 located in a right ventrolateral area of the spinal canal was diagnosed by magnetic resonance imaging. The herniated disc was removed through right hemilaminectomy and fenestration. The dog recovered quickly and returned to the owners 4 days after surgery with a slight lameness in the left pelvic limb. On the follow-up examination 2 months later the dog showed normal gait and normal neurological examination. Nerve root signature is not always indicative for the side of the lesion in case of lateralized intervertebral disc herniation

Accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints

Cervical zygapophysial joint nerve blocks typically are performed with fluoroscopic needle guidance. Descriptions of ultrasound-guided block of these nerves are available, but only one small study compared ultrasound with fluoroscopy, and only for the third occipital nerve. To evaluate the potential usefulness of ultrasound-guidance in clinical practice, studies that determine the accuracy of this technique using a validated control are essential. The aim of this study was to determine the accuracy of ultrasound-guided nerve blocks of the cervical zygapophysial joints using fluoroscopy as control.

Ultrasound-guided suprascapular nerve block, description of a novel supraclavicular approach

The suprascapular nerve (SSN) block is frequently performed for different shoulder pain conditions and for perioperative and postoperative pain control after shoulder surgery. Blind and image-guided techniques have been described, all of which target the nerve within the supraspinous fossa or at the suprascapular notch. This classic target point is not always ideal when ultrasound (US) is used because it is located deep under the muscles, and hence the nerve is not always visible. Blocking the nerve in the supraclavicular region, where it passes underneath the omohyoid muscle, could be an attractive alternative.

Ultrasound-guided retrobulbar nerve block in horses: a cadaveric study

Objective  To develop an ultrasound-guided technique for retrobulbar nerve block in horses, and to compare the distribution of three different volumes of injected contrast medium (CM) (4, 8 and 12 mL), with the hypothesis that successful placement of the needle within the retractor bulbi muscle cone would lead to the most effective dispersal of CM towards the nerves leaving the orbital fissure. Study design  Prospective experimental cadaver study. Animals  Twenty equine cadavers. Methods  Ultrasound-guided retrobulbar injections were performed in 40 cadaver orbits. Ultrasound visualization of needle placement within the retractor bulbi muscle cone and spread of injected CM towards the orbital fissure were scored. Needle position and destination of CM were then assessed using computerized tomography (CT), and comparisons performed between ultrasonographic visualization of orbital structures and success rate of injections (intraconal needle placement, CM reaching the orbital fissure). Results  Higher scores for ultrasound visualization resulted in a higher success rate for intraconal CM injection, as documented on the CT images. Successful intraconal placement of the needle (22/34 orbits) resulted in CM always reaching the orbital fissure. CM also reached the orbital fissure in six orbits where needle placement was extraconal. With 4, 8 and 12 mL CM, the orbital fissure was reached in 16/34, 23/34 and 28/34 injections, respectively. Conclusion and clinical relevance  The present study demonstrates the use of ultrasound for visualization of anatomical structures and needle placement during retrobulbar injections in equine orbits. However, this approach needs to be repeated in controlled clinical trials to assess practicability and effectiveness in clinical practice.