Nerve Hook Research Articles

A Polyimide Pressure-Contact Multielectrode Array for Implantation Along a Submillimeter Neural Process in Small Animals

We describe a microelectrode system for recordings from nerve bundles with diameters ranging from 20-200 microm. A novel polyimide structure allows for a planar microfabricated device to constrain a free neural process against several recording sites. This polyimide array contains multiple zigzag vias through which a small nerve process may be woven while remaining functionally intact in a live preparation. Our electrode construct features the benefits of nerve cuffs (evenly spaced electrodes in a polymer) and the functionality of a nerve hook (ability to connect to submillimeter processes). The device records extracellular action potentials in the red-swamp crayfish, Procambarus clarkii. Action potential propagation is monitored at several sites along a constrained nerve in this model organism's peripheral nervous system. Details of temporal accuracy and error sources in absolute conduction velocity measurements from microelectrode arrays are discussed.

Free bone cement fragments after minimally invasive unicompartmental knee arthroplasty: an underappreciated problem

The minimally invasive implantation of unicompartmental knee arthroplasty (UKA) leads to excellent functional results, but due to the reduced intraoperative visibility the removal of excessive cement may be difficult. In a retrospective study we assessed radiologically the incidence of loose and excess bone cement in 120 UKAs and correlated it to the thickness of the tibial cement layer. In 25 cases loose or attached excess cement was seen. Two of these patients with loose cement bodies required revision surgery. An additional 2 patients not operated at our institution required revision because of pain and loss of motion. The average thickness of the tibial cement layer was 3.1 (1.7-5.0) mm in all the patients. But it was significantly higher in the group with excess cement bodies [3.3 (2.3-5.0) mm] compared to the group without excess cement [3.0 (1.7-4.1) mm] (P < 0.05). Symptomatic free cement bodies need to be removed immediately, if necessary arthroscopically, in order to avoid damage to the implants. To avoid this problem in minimally invasive UKA, intraoperative fluoroscopy, a dental mirror or a nerve hook seem to be useful tools to identify and remove loose or excess cement.

Increased postoperative cervical myelopathy and cord compression resulting from the use of Gelfoam

Background context The immunogenicity of Gelfoam (Pharmacia and Upjohn, Kalamazoo, MI) or microfibrillar collagen, applied during laminectomy, may promote postoperative swelling and significant neural compression. Purpose To document how Gelfoam contributes to marked cord/root compression on unenhanced/enhanced postoperative magnetic resonance (MR) scans. Study design/setting This is a case report from the United States. Patient sample A case report. Outcome measure The patient's neurological status was assessed using Nurick Grades. Methods A 73-year-old female with moderate myeloradiculopathy (Nurick Grade III) and MR/computed tomography (CT)-documented cord compression underwent a C6/C7 laminectomy (undercutting of C5–T1) with Gelfoam applied to the laminectomy site, followed by a C2–T2 fusion for instability (iliac autograft, Beta TriCalcium Phosphate). Results The patient improved for the first postoperative week (Nurick Grade 0–I), but deteriorated over the successive second and third postoperative weeks (Nurick Grade III). When the 3-week postoperative MR study documented marked dorsolateral cord compression at the laminectomy site, likely attributed to a postoperative seroma/hematoma, a second operation was performed. At surgery, no significant seroma/hematoma was found. Rather, markedly engorged Gelfoam densely adherent to and compressing the underlying dura was encountered; this was meticulously removed under the operating microscope using a small nerve hook. Postoperatively, the patient immediately improved. As the intraoperative culture revealed Acinetobacter baumannii, she required 6 weeks of intravenous Ertapenem (1-betamethyl-carbapenem). The MR scan performed on the third postoperative week revealed no residual cord compromise. Conclusions Delayed postoperative deterioration in a 73-year-old female was attributed to reactive swelling/engorgement of Gelfoam at the C6–C7 laminectomy site.

Arthroscopic Management of Volar Lunate Facet Fractures of the Distal Radius

The clinical outcome of an intraarticular distal radius fracture is generally thought to be associated with the following factors: amount of radial deformity, joint congruity, and associated soft-tissue injuries. The proposed technique to manage this fracture pattern that involves a displaced volar lunate facet fragment uses wrist arthroscopy and pinning. Distraction of the fracture before arthroscopy is accomplished either by external fixation or by the arthroscopy tower. A freer elevator is introduced dorsally to disimpact the fragments, and next, a nerve hook is used to reduce the volar lunate facet, which is subsequently pinned to the radial styloid. The remaining fragments are reduced with interfragmentary pin fixation, and this anatomical articular construct is fixed to the radial metaphysis. The advantages of this technique are: (a) accurate assessment of articular congruency by direct visualization, (b) identification and repair of associated lesions, and (c) minimal soft tissue disruption. Potential disadvantages of external fixation supplemented by interfragmentary pins may be that it does not provide for rigid stable fixation, and therefore, does not allow for early motion compared to open reduction and internal fixation. Furthermore, it is technically challenging, and is therefore suggested as an alternative for the aforementioned fracture pattern.

Microplate osteosynthesis of orbital floor fractures

We present the outcome of transconjunctival osteosyntheis with a microplate of orbital floor fractures when there is nly a single fragment. Four patients with dislocated orbital oor fractures and diplopia were treated by osteosynthesis f the fractures between January 2004 and February 2005. ll four patients had double vision particularly on extreme ownward and upward gaze. The type and location of fracture as established by preoperative computed tomography. Two patients were operated on immediately after the njury and two patients after 7–10 days because of extenive periorbital swelling on admission. Intraoperatively we ecided to use osteosynthesis of the fractures only when we ound a single displaced fragment larger than 1.5 cm2. For extensive fractures with multiple fragments or defects e reconstructed the orbital floor and retrobulbar bulge with itanium mesh. The aim of osteosynthesis was anatomical eduction after removal of displaced orbital soft tissues and ony fragments from the maxillary sinus. We exposed the rbital floor by a transconjunctival approach without cantholsis and located the infraorbital nerve before osteosynthesis o protect it. The orbital fragment was fixed in the anterior aspect of he orbital floor using 1.0 and 1.3 mm microplates (Synthes, aoli, USA). It is difficult to fix screws in the posterior or entral part of the orbital floor because of angulation of the rill and unreliable anchorage of screws in thin bone. The ragment of the orbital floor was reduced and supported from nderneath during drilling (at high speed and low pressure) ith Gilles or nerve hooks. After the plate had been fixed nto the fragment with the first screw the bone was accurately educed. Bending of the plate allowed for precise reconstruc-

Combining the CO2Laser and the Endoscope to Remove Soft Tissue Masses from the Forehead Area

The aim of this study was to provide a retrospective analysis of treatment that combines the laser and the endoscope. Previously, surgeons faced many complications arising from endoscope-assisted surgery in the region of the forehead. In order to reduce the incidence of complications, such as swelling and hematoma, the CO2 laser is added to endoscope-assisted surgery. Between January 1996 and January 2003, 42 patients were treated for the removal of a benign tumor. The group was comprised of 18 males and 24 females, and their ages ranged from 5 to 64 years. The SurgiLase 150XJ CO2 laser system, used in conjunction with the flexible FIBERLASE (Sharplan, NJ), was used in all cases. The endoscope was 4 mm in diameter, with an angle of 30 degrees (Snoden Pancer, USA). The dissection was performed by relaying images from the endoscope to a monitor. The basic instrumentation consists of elevators, a nerve hook, retractors, and endoscopic scissors. Suction of the smoke generated by laser evaporization was also necessary. Of the 42 cases treated, 30 patients displayed lipomas, 10 patients displayed inclusion cysts, and two patients displayed dermoid cysts. After surgery, the follow-up period ranged from 6 months, to 2 years and 6 months, with an average of 1 year and 7 months. In this retrospective review, the incidences of early complications of these 42 patients included one case of scalp alopecia, three of scar alopecia, one of numbness, and three of ecchymosis. No hematoma cases were recorded. Evaluation after 6 months revealed the later complication of one scar alopecia. SurgiLase CO2 laser, used in conjunction with endoscopic surgery, enables plastic surgeons to work at a distance through small incisions without causing bleeding. Visible scars are reduced and recovery time is diminished.

The standard maze-III procedure

The standard maze-III procedure

Modification of the Hunsuck sagittal split osteotomy using a nerve hook. Technical note.

A modification of the Hunsuck mandibular sagittal split osteotomy is described by which a nerve hook is used to facilitate the optimum placement of the medial bone cut. The simple technique assists with the location of the lingula, protects the inferior alveolar nerve as it enters the mandibular foramen, and enables a bone cut to be placed into the mandibular foramen itself.

Modification of the Hunsuck sagittal split osteotomy using a nerve hook. Technical note

A modification of the Hunsuck mandibular sagittal split osteotomy is described by which a nerve hook is used to facilitate the optimum placement of the medial bone cut. The simple technique assists with the location of the lingula, protects the inferior alveolar nerve as it enters the mandibular foramen, and enables a bone cut to be placed into the mandibular foramen itself. Copyright 2002 European Association for Cranio-Maxillofacial Surgery. Published by Elsevier Science Ltd. All rights reserved.

Surgical retrieval of an embolized central venous catheter in a premature baby

Embolization of central venous catheter fragments is usually treated with percutaneous interventional techniques, which are difficult to apply in infants with very low birth weight. We surgically removed a catheter fragment in a preterm neonate, to avoid the impending thrombosis of the right pulmonary artery. The operation was performed with a nerve hook introduced through a tiny incision in the vessel’s wall. The procedure was well tolerated, and no stricture remains at the site of incision.

Use of cervicothoracic junction pedicle screws for reconstruction of complex cervical spine pathology.

A retrospective review of 21 patients in which cervical pedicle screw fixation was used at C7 with or without upper thoracic pedicle screw fixation. To evaluate the use of pedicle screw placement in the lower cervical spine. The use of posterior cervical spine fixation, including lateral mass fixation, has become increasingly popular in recent years. However, lateral mass fixation at C7 is often hindered by lack of substantial high quality bone. The end level of long cervical spine constructs is frequently C7 or T1. Dissatisfaction with lateral mass fixation at C7 and T1 led the authors to use lower cervical pedicle screw fixation for several cervical spine disorders. Twenty-one patients who had undergone cervical pedicle screw fixation at C7 were reviewed retrospectively. There were 12 males and 9 females, with an average age of 52 years. All pedicle screws were placed, after direct palpation of the pedicle, with a right angle nerve hook after laminoforaminotomy at C7. There were no neurologic complications related to pedicle screw placement, and no patient was symptomatically worse after the operation. Six patients with root pathology improved. Of 14 patients with cervical myelopathy, 12 improved at least one Nurick grade, and 2 had no improvement. There were no failures of fixation or complications related to pedicle fixation at a minimum of 1 year follow-up. Pedicle screws in C7 placed with laminoforaminotomy and palpation technique appears to be safe and efficacious. Excellent fixation can be achieved.

Extension of the “Elephant Trunk” Technique in Complex Aortic Pathology: The “Bidirectional” Option

Background. The “elephant trunk” technique, using a free-floating vascular prosthesis, was originally described to facilitate a subsequent operation on the downstream aorta. We developed an additional refinement of this technique, called the “bidirectional elephant trunk.” This option may represent an interesting tool in more complex aortic operations, especially when the descending aorta has to be replaced first in patients with concomitant pathology of the ascending aorta or of the aortic arch.Methods. The initial operation is performed through a left thoracotomy. The proximal elephant trunk is created by invaginating the future aortic arch graft into the descending aortic graft. The proximal anastomosis between the doubled graft and the proximal descending aorta is performed first. During construction of the distal anastomosis, a distal elephant trunk may be inserted likewise. If the aortic arch and ascending aorta have to be replaced later, this second step is performed through a median sternotomy. The free-floating arch graft is pulled out of the proximal descending aorta with a nerve hook, unfolded, and used for total arch replacement.Results. This technique was used successfully in 3 patients without mortality. No major complications were observed excepted persistent hoarseness in a patient with preoperative paresis of the recurrent nerve. No perfusion problems due to the unfolding of the free-floating graft occured during the second operation.Conclusions. The bidirectional elephant trunk technique is an interesting option that may be suitable for patients presenting with a complex pathology of the whole thoracic aorta when the descending segment has to be replaced first.(Ann Thorac Surg 1997;63:1755–8)

Balloon mitral commissurotomy: an intraoperative assessment.

Advances in balloon catheter technology have revolutionized the management of obstructive cardiovascular diseases. For lesions like mitral stenosis, balloon commissurotomy has emerged as an alternative to surgical relief showing definite functional benefits in a few clinical trials, albeit with variable results. Such variability necessitated objective evaluation of the efficacy of balloon mitral commissurotomy. The balloon mitral commissurotomy was carried out in 11 patients suffering from isolated mitral stenosis, under vision in a surgical setting. All patients were in NYHA class III/IV. Initially single balloon was used for mitral commissurotomy followed by double balloon, before completing the mitral valvotomy with surgical instruments whenever required. The commissural split was measured by firmly stretching the two commissures using nerve hooks and measuring the distance between the two hooks with the help of a caliper. Assessment of balloon dilation was made by calculating exact percentage of residual commissural split following balloon dilation as compared with completed mitral valvotomy. The exact percentage of commissural split was thus obtained by subtracting residual commissural split following balloon dilation from commissural split obtained after surgical open mitral valvotomy. Complete commissurotomy using the balloon technique was possible in two (18.2%) patients. In the remaining nine (81.8%) patients, balloon expansion provided only 50% to 80% of commissural split and required instrumental completion with good results. Balloon mitral commissurotomy, by virtue of its circumferential force, helps to develop a good cleavage and attains good hemodynamic improvement which may be life saving in critical mitral stenosis in selected group of patients with pliable mitral leaflets and minimal subvalvular pathology.

A Simple Technique for Precise Small Vessel Suture

This report describes a technique for accurate small-vessel closure that aids in preventing avoidable compromise of the lumen. In suturing a vessel opening by this method, the vessel is engaged and held by means of a nerve hook that obviates the use of customary thumb forceps (Fig 1). The assistant holds sustained traction on the suture, both to approximate edges of the incision and to create the transverse lattice of intravascular suture segments, CC′ (Fig 1, 2, and 3), against which the hook's foot applies pressure as it is gently pulled radially (Fig 1 and 3). The nerve hook serves not only as grasping forcep but as a jig for the precise selection of the points of insertion and emergence of the needle. (A jig is a device used to maintain mechanically the correct positional relationship between a piece of work and the tools working on it and/or between parts

A technique for end-to-side vascular anastomosis.

A technique of end-to-side venous anastomosis evolved during canine experiments at St. Luke's Hospital Laboratory seems to have advantages over the present technique. The first advantage of this technique is the reduced incidence of inadvertent suturing of the posterior suture line to the anterior suture line. In the past this has been achieved by placing traction sutures^{1 (p95)}or using nerve hooks²to separate the walls while suturing. Present techniques employ either a longitudinal incision³or excision of an elipse of the side wall.^1(p93)Upon completion of the anastomosis, there will be either a longitudinal slit or an oval opening at the suture line. The oval opening is said to have an advantage in maintaining patency. The technique described produces an adequate lumen by a different method. In this instance, anastomosis of the renal vein to the common iliac vein is described, but the method is