Martin Skie

Carpal tunnel changes and median nerve compression during wrist flexion and extension seen by magnetic resonance imaging

Magnetic resonance imaging was done on the wrists of 14 volunteer subjects with the wrists in the neutral position, then flexed and extended at 45 degrees. Computer enhanced cross-sectional areas were measured on each subject at the level of the hook of the hamate. In the neutral position the distance between confining structures around the median nerve is 2.0 +/- 0.2 mm in the anteroposterior direction, and the mean cross-sectional area of the carpal tunnel is 1.52 cm2. With the wrist in the extended position the distance available for the median nerve measures 2.2 +/- 0.4 mm and the cross-sectional area increases to 1.75 cm2. When the wrist is flexed, the distance available for the median nerve between the flexor tendons and transverse carpal ligament decreases to 1.1 +/- 0.4 mm, and the cross-sectional tunnel area decreases to 1.36 cm2. Flexion of the wrist and/or fingers both produces a palmar rearrangement of the flexor tendons creating potential compression of the median nerve. The nerve responds to these forces by becoming interposed in various positions between the superficial flexor tendons.

Radiographic and Computed Tomographic Evaluation of Lisfranc Dislocation: A Cadaver Study

Six cadaver feet were used for radiological and computed tomographic (CT) evaluation. The tarsometatarsal joints of each specimen were displaced dorsolaterally in successive 1-mm increments. None of the 1-mm and two thirds of the 2-mm dorsolateral Lisfranc dislocations could be visualized on routine radiographs; they could all be noted on CT scans. There was good assessment on CT scan for the extent of the minor lesions that are normally obscured by overlapping projection in routine radiographs. A Lisfranc injury that appears undisplaced on radiographs or acceptable after closed reduction may still have an unpredictable outcome because of the presence of an occult joint subluxation. CT scanning is more sensitive than radiography for detecting the minor amounts of Lisfranc displacement. If there is any doubt on the radiographs, a CT scan should be performed. The early diagnosis and treatment of Lisfranc injuries may minimize development of post-traumatic degenerative arthritis.

Vulnerability of the recurrent laryngeal nerve in the anterior approach to the lower cervical spine

Study Design. To perform anatomic dissections and measurements of the recurrent laryngeal nerve between the inferior thyroid artery and superior border of the clavicle (mid‐portion) on both sides. Objectives. To determine quantitatively the differences in course and location between the recurrent laryngeal nerves on both sides and to relate this to the vulnerability of the recurrent laryngeal nerve during an anterior approach to the lower cervical spine. Summary of Background Data. The midportion of the recurrent laryngeal nerve is usually encountered in the anterior approach to the lower cervical spine, especially on the right side. No quantitative regional anatomy describing the course and location of the mid‐portion of the recurrent laryngeal nerve is available in the literature. Methods. Fifteen adult cadavers were used for dissections of the recurrent laryngeal nerve. The length of the recurrent laryngeal nerve between the superior border of the clavicle and the inferior thyroid artery, and the angle of the recurrent laryngeal nerve with respect to sagittal plane, were measured bilaterally. In addition, six cross‐sections at C7 were obtained to determine the linear distances between esophagotracheal groove and the recurrent laryngeal nerve. Results. The recurrent laryngeal nerve on the right runs in a superior and medial direction, with an angle of 25.0° ± 4.7° relative to sagittal plane, compared with 4.7° ± 3.7° on the left. The length of the recurrent laryngeal nerve between the superior border of the clavicle and the inferior thyroid artery is 23.0 ± 4.4 mm on the left, and 22.8 ± 4.3 mm on the right. The recurrent laryngeal nerve lies deep within the esophagotracheal groove on the left, but 6.5 ± 1.2 mm anterior and 7.3 ± 0.8 mm lateral to the esophagotracheal groove on the right. Conclusions. The recurrent laryngeal nerve on the right side is highly vulnerable to injury if ligature of the inferior thyroid vessels is not performed as laterally as possible or if retraction of the midline structures along with the recurrent laryngeal nerve is not performed intermittently. Avoiding injury to the recurrent laryngeal nerve, especially on the right side, is a major consideration during an anterior approach to lower cervical spine.

Evaluation of process fractures of the talus using computed tomography.

Summary: Coronal computed tomography (CT) scan was used in the evaluation of a fractured process of the talus in 10 patients. Because routine radiographs failed to determine either the size or comminution of the fractured process, CT imaging was used to accurately assess the size, displacement, and comminution of the fractured process. CT scans also showed the extent of subtalar joint involvement, any associated tendon pathology, or additional fractures. In two patients the nature of the injury was initially missed, and CT scan diagnosed a nonunion of the lateral process. In all patients, CT scan altered the management of the fracture or helped in selecting the surgical approach. The authors recommend that coronal CT scans be used in the evaluation of a fractured process of the talus

The treatment of tibial nonunion with angular deformity using an Ilizarov device

Nine patients with nonunion of the tibia associated with angular deformity were treated using the Ilizarov device. Eight of these went on to heal the nonunion and had acceptable correction of the angular deformity. One patient with an atrophic nonunion and severe bone loss received a below knee amputation. The authors recommend the use of circular ring fixation as an alternative in the treatment of selected cases of stiff nonunion of the tibia combined with angular deformity, particularly if there is active infection, prior use of an external fixator, or poor soft tissue coverage.

Operative technique for inside-out repair of the triangular fibrocartilage complex.

A technique for arthroscopic inside-out repair of peripheral traumatic (type 1B) tears of the triangular fibrocartilage complex is reported. The technique can be performed using zone-specific cannulas that are commonly used for repairing meniscal tears in the knee. Anatomic dissections were used to show the safe regions around the TFCC where tears are amenable to this type of repair.

Radiological evaluation of peroneal tendon pathology associated with calcaneal fractures

Review of MRI, CT, and radiographic views of 21 intraarticular calcaneal fractures revealed eight cases of peroneal tendon subluxation or dislocation. Routine radiographs were nondiagnostic for the soft tissue injury in five of these eight patients. The anatomic relationships between the tendons, retinaculum, and fibular groove could typically be identified easily on MRI or CT scan. In this combined injury, recognition of the peroneal tendon subluxation or dislocation and its proper management may reduce subsequent tendon dysfunction; it may also alter the calcaneal fracture management.

Coronal Fracture of the Body of the Hamate

Fractures of the body of the hamate are unusual. Eleven patients with coronal fractures of the hamate bone, all involving dislocation of the hamate-metacarpal joint, are reported. Routine roentgenograms were not helpful in delineating the presence of the injury in five patients; therefore, fracture diagnosis was not initially made in those patients. The average delay in diagnosis of this group was 10 days. A 30-degree pronated view, tomograms, and computed tomography scans may be necessary in the diagnosis of this injury. This fracture was found to be highly unstable. Ten patients underwent surgery for stabilization of their fractures and restoration of the congruity of the hamate-metacarpal joint. Four patients were treated with open reduction and internal fixation of the fracture. Six patients were treated with closed reduction and percutaneous pinning. All patients treated surgically had maintenance of reduction of their joints. One patient was treated with closed reduction and casting; reduction in this case was lost, and the patient developed residual subluxation of the hamate-metacarpal joint.

Medial Subtalar Dislocation Associated With Fracture of the Posterior Process of the Talus: A Case Report

A 27 year-old man was involved in a high-energy-impact motor-vehicle accident and sustained multiple injuries including a medial subtalar fracture dislocation. The dislocation of the subtalar joint was reduced by closed means, but a large, comminuted, displaced posterior process fracture remained. Open reduction and internal fixation through a posteromedial approach with mobilization of the neurovascular bundle was used to restore congruity to the subtalar joint.

Cervical uncinate process: an anatomic study for anterior decompression of the cervical spine

Morphometric evaluation of 54 dry cervical spines from C3 to C7 (a total of 270 cervical vertebrae) was performed to determine the bony boundaries of the uncinate process for resection of the uncinate process for access to posterolateral osteophytes or herniated disks at the time of anterior cervical diskectomy. The uncinate processes were significantly higher (p < 0.01) at the C4 - C6 levels (5.8 ± 1.1 mm to 6.1 ± 1.3 mm) than at the C3 or C7 levels. The distance between the medial and lateral margins of the base of the uncinate process was significantly smaller (p < 0.01) at the C3 level (4.9 ± 0.7 mm) than at the C7 level (6.3 ± 0.7 mm). The anteroposterior diameter of the medial margin of the uncinate process decreased gradually from the C5 (12.5 ± 1.5 mm) to C7 levels (11.6 ± 1.3 mm) (p < 0.05). The inter-uncinate distance widened from the C3 (19.2 ± 1.5 mm) to the C7 (24.6 ± 2.1 mm) levels (p < 0.01). The mid-anteroposterior diameter of vertebral body increased gradually from the C3 (14.7 ± 1.1 mm) to the C7 levels (16.1 ± 1.5 mm) (p < 0.01). The width of the vertebra increased gradually from C3 to C7 (from 19.2 ± 1.8 mm at C3 to 25.6 ± 2.0 mm at C7) (p < 0.01). Knowledge of all the aforementioned data may be helpful during anterolateral cervical uncosectomy or uncoforaminotomy.