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PubMed1999

Anatomic study of the lateral femoral cutaneous nerve with respect to the ilioinguinal surgical dissection.

OBJECTIVE: To report on the anatomic variations of the lateral femoral cutaneous nerve with respect to the ilioinguinal surgical dissection. DESIGN: Cadaveric anatomic study. PATIENTS/PARTICIPANTS: Sixty-eight ilioinguinal dissections performed in fifty cadavers. INTERVENTION: The lateral femoral cutaneous nerve was identified, and certain location variables were recorded. MAIN OUTCOME MEASURE: The distance in millimeters from the medial edge of the anterior superior iliac spine (ASIS), whether the nerve was lateral or medial to the ASIS, and the layer in which the nerve crossed the dissection. RESULTS: In seven dissections, the nerve was twenty-one to twenty-five millimeters medial to the ASIS; in ten dissections, the nerve was twenty-six to thirty millimeters from the ASIS; and in fourteen dissections, the nerve was more than thirty millimeters medial to the superior border of the ASIS. The average medial distance from the ASIS was 20.4 millimeters, with a range of three to forty-six millimeters. In no specimen did the nerve pass lateral to the ASIS. The lateral femoral cutaneous nerve was found to lie anterior to the iliopsoas muscle in all specimens. CONCLUSION: The course of the lateral femoral cutaneous nerve is highly variable; the nerve was most commonly found at ten to fifteen millimeters from the ASIS and as far medially as forty-six millimeters. When using the illioinguinal surgical approach, if the lateral femoral cutaneous nerve is not encountered immediately adjacent to the ASIS, dissection up to five centimeters medial to the ASIS may be necessary to locate the nerve.

Cadaver↗

PubMed1996

Injury pattern and severity in lateral motor vehicle collisions: a Canadian experience.

OBJECTIVE: To determine the pattern and severity of injury and the outcome of front seat motor vehicle occupants after lateral impact crashes. DESIGN: Retrospective review undertaken in a Regional Trauma Unit (Sunnybrook Health Science Centre). MATERIALS AND METHODS: Review of seriously injured front seat motor vehicle occupants admitted to a Regional Trauma Unit over a 46-month period (September 15, 1989, to July 15, 1993) for whom vehicle crash information and occupant seat belt use were known. MEASUREMENTS AND MAIN RESULTS: Three hundred forty-eight front seat vehicle occupants were available for study; one hundred forty-one (41%) were involved in a lateral impact motor vehicle crash. Driver side lateral crashes (57%) were more common than passenger side impacts. Victims of lateral impact crashes had a significantly higher mean Injury Severity Score (25 compared with 20 for nonlateral crashes: p < 0.05), and the direction of impact was strongly associated with injury severity (p < 0.05). Lateral impact crashes resulted in substantially more significant chest (p < 0.01) and intra-abdominal (p < 0.0001) injuries. Type of injury was significantly different between the lateral and nonlateral impact groups for facial, chest, abdominal, and musculoskeletal injuries. CONCLUSIONS: The direction of impact in motor vehicle crashes is strongly associated with the pattern and severity of organ injuries. Further attention to automobile safety design is necessary to better protect occupants involved in lateral impact crashes.

Accidents, Traffic↗

PubMed1999

Influence of lateral osteotomies in the dimensions of the nasal cavity.

OBJECTIVES: To elucidate the importance of placement of lateral osteotomy in rhinoplasty at a level above or below the insertion of the inferior turbinate at the pyriform aperture. STUDY DESIGN: Controlled lateral osteotomies were performed in 16 cadaver noses. Eight of the lateral ostetomies were placed below (low) and eight were placed above (high) the insertion of the inferior turbinate. In all 16 noses medial osteotomies were performed. Dimensions of the nasal cavity were measured by acoustic rhinometry before and after the osteotomies. METHODS: The total minimum cross-sectional area (TMCA) and the cross-sectional area at the pyriform aperture (TCA-3.3) were calculated and the preoperative and postoperative values were analyzed statistically. RESULTS: There was no significant difference in the reduction of cross-sectional area in the group that underwent high lateral osteotomy compared with the group the underwent low lateral osteotomy. In both groups the TMCA was reduced, with 12% of the value (P = .001) before osteotomy, and the TCA-3.3 was reduced, with 15% of the value before osteotomy (P = .000). CONCLUSIONS: After lateral and medial ostetomies a significant decrease in the anterior dimensions of the nose is observed. The decrease following osteotomy does not seem to be due to the placement of the lateral osteotomy at the pyriform aperture but rather to the detachment of the bony vault from the surrounding structures.

Cadaver↗

PubMed2003

Lateral pharyngoplasty: a new treatment for obstructive sleep apnea hypopnea syndrome.

OBJECTIVE: The role of the lateral pharyngeal muscular walls in the pathogenesis of obstructive sleep apnea hypopnea syndrome (OSAHS) is crucial. My objective is to describe a surgical procedure for splinting the lateral pharyngeal walls in patients with OSAHS and report the initial results. STUDY DESIGN: Prospective randomized pilot study performed in an academic tertiary center as part of a doctoral thesis. PATIENTS AND METHODS: Ten adults with OSAHS, originally selected for treatment with uvulopalatopharyngoplasty, underwent the lateral pharyngoplasty procedure, which consists of a microdissection of the superior pharyngeal constrictor muscle within the tonsillar fossa, sectioning of this muscle, and suturing of the created laterally based flap of that muscle to the same-side palatoglossus muscle. In addition, a palatopharyngeal Z-plasty is performed to prevent retropalatal collapse. RESULTS: Lateral pharyngoplasty improved sleep and daytime symptoms related to OSAHS. After at least 6 months of follow-up, the median apnea-hypopnea index decreased from 41.2 to 9.5 (P =.009) and the median total sleep time spent in rapid eye movement (REM) sleep and in stages 3 plus 4 non-REM sleep increased from 14.1% to 22.1% (P =.059) and from 5.3% to 16.3% (P =.037), respectively. Also, there was statistically significant improvement in snoring, daytime sleepiness, and overall impact of the disease on quality of life. Swallowing disturbances lasted a median of 14.5 days after the surgeries, and all patients returned to normal subjective swallowing function in the follow-up. CONCLUSIONS: Lateral pharyngoplasty is a safe and straightforward approach to lateral pharyngeal muscles and has produced appreciable benefits for OSAHS patients.

Adult↗

PubMed2001

Aneurysms of the lateral spinal artery: report of two cases.

OBJECTIVE AND IMPORTANCE: The goal of this report was to describe aneurysms arising from the lateral spinal artery. The locations of aneurysms contributing to subarachnoid hemorrhage (SAH) have been well characterized and are primarily in the circle of Willis or at the bifurcation points of the internal carotid artery or the vertebrobasilar system. Although the spinal arteries are also in direct communication with the subarachnoid space, aneurysms of these arteries that lead to SAH are rare. To date, only aneurysms of the anterior and posterior spinal arteries have been described. In this communication, we report two patients with aneurysms of the lateral spinal artery who presented with SAH. CLINICAL PRESENTATION: Review of our neurointerventional database from 1997 to the present revealed two patients with lateral spinal artery aneurysms. The medical records, as well as the operative and radiological findings, were reviewed for both patients. In both cases, the lateral spinal arteries were involved as collateral pathways for occlusive vertebral lesions, suggesting hemodynamic stress as a cause. INTERVENTION: Endovascular treatment was attempted in both cases and was successful in one; open surgery, with aneurysm resection, was performed in the other case. We review the vascular anatomic features of the spinal cord as they relate to the lateral spinal artery, as well as treatment options for lateral spinal artery aneurysms. CONCLUSION: Lateral spinal artery aneurysms are a rare cause of SAH. Both endovascular and surgical treatment options are available.

Aged↗

PubMed1995

High-lateral-tension abdominoplasty with superficial fascial system suspension.

Modern abdominoplasty techniques were developed in the 1960s. The advent of liposuction has reduced the need for classic abdominoplasty and allowed more aesthetic sculpting of the entire trunk. However, the combination of significant truncal liposuction and classic abdominoplasty is not recommended due to the increased risk of complications. Although the surgical principles of classic abdominoplasty certainly have stood the test of time, they are based on two theoretical assumptions that may be proved to be inaccurate. The first assumption is that wide direct undermining to costal margins is essential for abdominal flap advancement. In fact, discontinuous undermining allows effective loosening of the abdominal flap while preserving vascular perforators. The second inaccurate assumption is that with aging and weight fluctuations (including pregnancy), abdominal skin relaxation occurs primarily in the vertical direction from the xiphoid to the pubis. This is true in the lower abdomen, but in most patients a strong superficial fascial system adherence to the linea alba in the epigastrium limits vertical descent. Epigastric laxity frequently results from a progressive horizontal loosening due to relaxation of the tissue along the lateral trunk. Experience with the lower-body lift procedure has shown that significant lateral truncal skin resection results in epigastric tightening. In these patients, the ideal abdominoplasty pattern would resect as much or more laterally than centrally, leading to more natural abdominal contours. Fifty patients who underwent high-lateral-tension abdominoplasty with and without significant truncal liposuction and other aesthetic procedures were followed for 4 to 16 months. The primary indication for surgery was moderate to severe laxity of abdominal skin and muscle with or without truncal fat deposits. Complication rates were equal to or less than those of historical controls and did not increase with significant adjunctive liposuction. The key technical elements of this procedure include direct undermining limited to the paramedian area, discontinuous undermining to costal margins and flanks as needed, skin resection pattern with significant lateral resection and highest-tension wound closure placed laterally, superficial fascial system repair with permanent sutures along the entire incision, and liberal use of adjunctive liposuction in the upper abdomen and the lateral and posterior trunk.

Abdominal Muscles↗

PubMed2002

Surgical anatomy of the ligamentous attachments of the lower lid and lateral canthus.

Description of the surgical anatomy of the superficial fascia of the face must include its deep attachments. These attachments have been mapped out for the forehead, temple, and cheek as retaining ligaments. The deep attachments of the orbicularis oculi of the lower lid and lateral canthus have long been recognized in canthopexy surgery but have yet to be properly defined. Six fresh cadavers were dissected with histologic support, and the results were correlated with surgical observations. The fascia of the deep aspect of the orbicularis is attached to the periosteum of the orbital rim by an orbicularis retaining ligament. This attachment is weakest centrally and tightest over the inferolateral orbital rim. The retaining ligament fuses with an expanded fibrous attachment beyond the lateral canthus, the lateral orbital thickening, which extends over the lateral orbital rim onto the adjacent deep temporal fascia. Aging changes are associated with attenuation of the ligamentous support provided by the orbital thickening and the orbicularis retaining ligament, which then allows inferior displacement of the lower boundary of the lid and contributes to the typical effects of age in this region. The superficial fascia of the lateral orbital region has a continuous connective tissue structure linking the temporoparietal fascia and orbicularis fascia to the lateral canthal tendon by means of the tarsal plate connection. Release of the deep ligamentous attachments (lateral orbital thickening and orbicularis retaining ligament) of the orbicularis fascia is important in some canthopexy and in rejuvenation procedures. The release allows effective redraping and upward mobilization of the orbicularis of the lower lid and the premalar soft tissues.

Aged↗

PubMed1995

Human trunk strength profile in lateral flexion and axial rotation.

STUDY DESIGN: To determine the functional capability in asymmetric trunk motion, isometric and isokinetic lateral flexion and axial rotation strengths of a normal and patient samples were measured. Seventy-three normal asymptomatic subjects (41 males and 32 females) and ten patients (9 males and 1 female) were tested. OBJECTIVES: The dual objectives of the study were to develop a database for isometric and isokinetic lateral flexion and axial rotation strength capabilities of a normal sample and to determine the functional impairment of a sample of patients. SUMMARY OF BACKGROUND DATA: More than 60% of low back injuries are associated with trunk twisting. Asymmetric motions are important risk factors. However, strength capability data for axial rotation are sparse and those for lateral flexion nonexistent. METHODS: To achieve the objectives of the study, two devices were designed and fabricated. Isometric lateral flexion was tested bilaterally in neutral posture and at 10 degrees, 20 degrees, and 30 degrees of lateral bending. Isometric axial rotation was tested bilaterally in neutral posture and at 5 degrees, 10 degrees, 15 degrees, and 20 degrees of axial rotation. Isokinetic lateral flexion and axial rotation strengths were tested bilaterally starting from the neutral posture. RESULTS: The strength invariably declined progressively for all groups with increasing postural asymmetry. The strength in isokinetic activities ranged between 60% to 70% of the strength measured in isometric activities. All groups were significantly stronger in lateral flexion compared with axial rotation. The female sample ranged between 60% to 70% values of males for all activities studied. The patient group was weakest, ranging between 45% to 55% for isometric and 52% to 58% for isokinetic activities of their control group.

Adult↗

PubMed1997

Rigid internal fixation with lateral mass plates in multilevel anterior and posterior reconstruction of the cervical spine.

STUDY DESIGN: A retrospective clinical and radiographic analysis was performed on 17 patients with multilevel cervical disease who were treated with anterior and posterior reconstruction with a new rigid, segmental, internal fixation system applied to the lateral masses. OBJECTIVES: To determine the applicability, safety, and clinical efficacy of an instrumentation system used as a cervical lateral mass plate in the management of complex spinal disorders. SUMMARY OF BACKGROUND DATA: Cervical disorders involving three or more levels present a difficult reconstruction problem, especially if the posterior elements are deficient. Segmental fixation with lateral mass plating provides an alternative method to situations that would otherwise require a halo. METHODS: Seventeen patients treated by a single surgeon underwent cervical reconstruction surgery involving three or more levels. All patients had anterior decompression and reconstruction and a posterior fusion with rigid internal fixation with a device applied to the lateral masses of the cervical vertebrae. Patients were reviewed clinically and radiographically to determine the efficacy and safety of this method of fixation. RESULTS: Of the 15 patients with adequate follow-up data that were studied, the condition of 13 patients, (87%) was improved, that of one patient (6.7%) was the same, and that of another (6.7%) was worse after surgical intervention. Sagittal alignment was restored to within 5 degrees of the preoperative lordosis in active extension by the modified Cobb method and the Gore method. No patient had radiographic nonunion. One patient had a sensory radiculopathy associated with an overpenetrated lateral mass screw that partially resolved after hardware removal. One patient had asymptomatic loosening of a C7 lateral mass screw. CONCLUSIONS: Segmental posterior fixation with lateral mass plating provides more rigid immobilization than traditional techniques, allows restoration and maintenance of spinal alignment, obviates the need for halo immobilization, and is associated with a low incidence of neurovascular injury.

Adult↗

PubMed1997

Cervical pedicle screws versus lateral mass screws. Anatomic feasibility and biomechanical comparison.

STUDY DESIGN: Biomechanical comparison of the pull-out strengths of lateral mass and pedicle screws in the human cervical spine. Measurements of pedicle dimensions and orientation were compiled. OBJECTIVES: To determine if transpedicular screws provide greater pull-out resistance than lateral mass screws and to investigate the anatomic feasibility of pedicle screw insertion. SUMMARY OF BACKGROUND DATA: Cervical pedicle screws have been reported in limited clinical and biomechanical studies, and some quantitative cervical pedicle anatomy has been reported. No direct biomechanical comparisons have been made between lateral mass and pedicle screws. METHODS: Fifty-six fresh disarticulated human vertebrae (C2-C7) were evaluated with computed tomography to determine morphometry and vertebral body bone density. Lateral mass and pedicle screws were randomized to left versus right. A 3.5-mm cortical screw was used for both techniques, unless a pedicle was narrower than 5.0 mm; then a 2.7-mm cortical screw was used instead. Pedicle wall violations were recorded. Screws were subjected to a uniaxial load to failure. Mean pedicle height, width, and angle with respect to the vertebral midline were tabulated for each level. RESULTS: The mean load-to-failure was 677 N for the cervical pedicle screws and 355 N for the lateral mass screws. No significant correlations for either screw type were found between pull-out strength and bone density, screw length, or vertebral level. Pedicle and lateral mass dimensions were highly variable and not predictive of pull-out strength. Seven (13%) minor pedicle wall violations were observed. CONCLUSIONS: Cervical pedicle screws demonstrated a significantly higher resistance to pull-out forces than did lateral mass screws. The variability in pedicle morphometry and orientation requires careful preoperative assessment to determine the suitability of pedicle screw insertion.

Biomechanical Phenomena↗

PubMed1999

The surgical treatment of far lateral L3-L4 and L4-L5 disc herniations. A modified technique and outcomes analysis of 25 patients.

STUDY DESIGN: A retrospective review of 25 patients who underwent a modified surgical procedure for the treatment of far lateral disc herniation. OBJECTIVES: To describe a modification of previous surgical techniques for the treatment of far lateral disc herniation and to review the outcomes in resolution of pain and improvement of functional status. SUMMARY OF BACKGROUND DATA: Lumbar disc herniations that occur far lateral to the intervertebral facet result in spinal nerve compression at L3-L4 and L4-L5. Previous surgical techniques have resulted in an increased risk of instability or continued postoperative back pain. METHODS: Twenty-five patients with far lateral disc herniation underwent surgery using an extreme lateral approach. There was no medial facetectomy or disruption of the pars interarticularis. The intertransverse ligament was released from the superior portion of the inferior transverse process, and the nerve was located before removal of the disc. Preoperative and postoperative visual analog pain scale and Oswestry functional status evaluation were reviewed along with complications to evaluate the efficacy of the surgery. RESULTS: No serious complications were noted, although transient neuropathic pain was common and was theorized to be caused by manipulation of the dorsal root ganglion during surgery. This pain was usually resolved within 4 to 6 weeks. The mean preoperative and postoperative visual analog scale scores were 7.7 and 4.2, respectively. The mean preoperative and postoperative Oswestry scores were 50.7% and 34.7%, respectively. Both of these improvements were statistically significant (P < 0.01). CONCLUSIONS: This far lateral approach allowed the nerve and far lateral disc herniations to be easily identified. Also, there was less blood loss and no medial facetectomy or disruption of the pars interarticularis. This is a safe, effective technique with no disruption of spinal stability.

Aged↗

PubMed2001

Facet tropism: a comparison between far lateral and posterolateral lumbar disc herniations.

STUDY DESIGN: An assessment of the difference in the degree of facet tropism and disc degeneration between far lateral and posterolateral lumbar disc herniations. OBJECTIVE: To investigate the effect of the difference in the degree of the facet tropism and disc degeneration with respect to the development of far lateral lumbar disc herniation and posterolateral lumbar disc herniation, and to compare the effect between the two types of herniations. SUMMARY OF BACKGROUND DATA: The effect of facet tropism on the development of posterolateral lumbar disc herniation has been investigated previously, but there has been no study on far lateral lumbar disc herniation. METHODS: Thirty-eight lumbar disc herniations (far lateral, n = 19; posterolateral, n = 19) were included this study. The degree of facet tropism and disc degeneration was measured at the herniated disc level by using magnetic resonance imaging. The results were compared to show any differences between the two types of lumbar disc herniations. RESULTS: There were significant differences in the degree of facet tropism (24.74 vs. 14.26, P = 0.004) and disc degeneration (23.92 vs. 15.08, P = 0.005) between the far lateral and posterolateral lumbar disc herniations. There was no significant correlation between the degree of facet tropism and the degree of disc degeneration in far lateral lumbar disc herniation (r = -0.369, P = 0.120). CONCLUSION: This results suggest that the differences in the degree of facet tropism and disc degeneration might be considered a key factor in distinguishing the development of far lateral lumbar disc herniation from that of posterolateral lumbar disc herniation.

Adult↗

PubMed2005

Lateral femoral cutaneous nerve: an anatomic study.

The purpose of our study was to determine the location of the lateral femoral cutaneous nerve and its branches at the inguinal ligament and proximal thigh. We think that further defining the location of the nerve and its branches based on certain measurements from known anatomic landmarks would enable us to determine a danger zone that could aid in preventing iatrogenic injury to the lateral femoral cutaneous nerve. The anatomic course of the lateral femoral cutaneous nerve was studied in 29 cadaver specimens and distances from various landmarks were recorded. In addition, the branching pattern of the nerves was recorded. We observed variability in the course and branching patterns of the lateral femoral cutaneous nerve. The lateral femoral cutaneous nerve was found to potentially be at risk as far as 7.3 cm medial to the anterior superior iliac spine along the inguinal ligament and as much as 11.3 cm distal on the sartorius muscle from the anterior superior iliac spine. As many as five branches of the lateral femoral cutaneous nerve were found and in 27.6% of cases the lateral femoral cutaneous nerve branched before traversing the inguinal ligament. We used this information to describe a danger zone, which could be used as a guide to help prevent unnecessary injury during certain procedures.

Adult↗

PubMed2004

Cervical muscle response to whiplash-type right lateral impacts.

STUDY DESIGN: Nine healthy volunteers were subjected to right lateral impacts of 4.9, 8.8, 10.8, and 13.7 m/sec acceleration at two levels of expectation: expected and unexpected. OBJECTIVES: To determine the response of the cervical muscles to increasing low-velocity right lateral impacts and compare the quantitative effects of expected and unexpected impact. SUMMARY OF BACKGROUND DATA: The literature contains little information on the etiology of whiplash injuries. In particular, in vivo studies of the cervical muscular response and head-neck kinematics to lateral impacts are rare. A previous study of left lateral impacts suggests that the burden of impact is borne primarily by the muscles contralateral to the side of impact. METHODS: Bilateral electromyograms of the sternocleidomastoids, trapezii, and splenii capitis were recorded. Triaxial accelerometers recorded the acceleration of the chair, torso at the shoulder level, and head of the participant. RESULTS: At an acceleration of 13.7 m/sec2, both sternocleidomastoids, both trapezii, and the right splenius capitis generated on average around 40% or less of their maximal voluntary contraction electromyogram in both the expected and unexpected impact conditions. The left splenius capitis (i.e., contralateral to the right lateral impact), however, generated 84% of its maximal voluntary contraction electromyogram (double the response of other muscles). Electromyographic variables were affected significantly by the levels of acceleration (P < 0.01). The time to onset and time to peak electromyogram time for all muscles decreased progressively with increasing levels of acceleration. The kinetic variables and the electromyographic variables regressed significantly on the acceleration (P < 0.01), and the head acceleration was affected significantly by expectation (P < 0.01). In response to right lateral impacts, muscle responses were generally greater, with higher levels of acceleration, and greatest for the splenius capitis muscle contralateral to the side of impact (P < 0.01). CONCLUSIONS: Because the muscular component of the head-neck complex likely plays a central role in the abatement of higher acceleration levels, it may be a primary site of injury in the whiplash phenomenon in lateral collisions, and specifically, the splenius capitis muscle contralateral to the side of impact is most likely to be injured. Being aware of an impact may reduce the degree of head perturbation.

Acceleration↗

PubMed2006

Degenerative lumbar scoliosis: radiographic correlation of lateral rotatory olisthesis with neural canal dimensions.

STUDY DESIGN: A radiographic review of 78 consecutive patients with degenerative rotatory lumbar scoliosis. OBJECTIVE: To assess the correlation between rotary olisthesis and neural canal dimensions using radiographic indexes and to establish a gradation system of lateral rotatory olisthesis. SUMMARY OF BACKGROUND DATA: Degenerative scoliosis is a three-dimensional deformity often associated with spinal stenosis, although the association is not well defined. METHODS: A total of 78 consecutive patients (average age, 69 years) with de novo degenerative scoliosis (79% lumbar, 21% thoracolumbar; average curve, 25 degrees) were studied with plain radiographs and MRI at presentation. Radiographic measurements included lateral translation, anteroposterior olisthesis, Cobb angle, and intervertebral rotation (Nash-Moe grade difference). Computerized measurements of MRI included dural sac cross-sectional area and anteroposterior diameter, minimum subarticular height, and foramen cross-sectional area bilaterally (convexity and concavity). Measurements were conducted twice on each lumbar level (total, 312) and the average was recorded. RESULTS: Lateral translation 5 mm or less (Grade I) was associated with Nash-Moe change 0 (23%) or I (77%), lateral translation 6-10 mm (Grade II) was coupled with Nash-Moe change 0 (20%) or I (80%) and lateral deviation more than 11 mm (Grade III) was associated with I (76%) or II (24%) Nash-Moe change. Maximum intervertebral rotation tended to be at either L2-L3 (48%) or L3-L4 (39%). Increased lateral translation was associated with increased intervertebral rotation (r = 0.37, P < 0.001). Increased anteroposterior olisthesis was associated with decreased anteroposterior diameter (r = -0.18, P < 0.001) and cross-sectional area (r = -0.11, P < 0.05) of the dural sac. Larger segmental Cobb angles were associated with greater foraminal cross-sectional area in the convexity (r = 0.12, P < 0.05). In the concavity, there was no significant correlation (P > 0.05) between indexes of rotary olisthesis and foraminal area or subarticular height. Cross-sectional foraminal area and subarticular height were significantly larger in the convexity than in the concavity of the scoliotic levels. CONCLUSIONS: In degenerative scoliotic curves, lateral translation is associated with rotation. Increased rotary olisthesis does not lead to decreased dural sac area. Anteroposterior olisthesis is inversely correlated to the dural sac anteroposterior diameter and cross-sectional area. With increased segmental Cobb angle, foraminal cross-sectional area enlarges in the convexity and does not decrease in the concavity. Presence of intervertebral rotation alone does not appear to be associated with reduced neural canal dimensions. Ligamentum flavum hypertrophy, posterior disc bulging, and bony overgrowth are more likely to contribute to stenosis irrespective of scoliosis.

Aged↗

PubMed2005

Posterior cervical lateral mass screw fixation: analysis of 1026 consecutive screws in 143 patients.

OBJECTIVE: This study evaluates the results and complications of 1026 consecutive lateral mass screws inserted in 143 patients by a single surgeon. METHODS: Over a 50-month period, a total of 1026 lateral mass screws were placed in 143 patients ages 12-96 years (56 females and 87 males), with these records retrospectively reviewed. Screw position was evaluated by computed tomography (CT) scanning postoperatively, with screw positions assessed for facet, foraminal, or foramen transversarium violation. RESULTS: All screws were placed by a modification of the Anderson technique, but 20 screws were converted to Roy-Camille trajectories because of screw pullout. No patients experienced neural injury or vertebral artery injury as a result of screw placement. Three patients had screw pullouts using the Axis system, which did not require reoperation. Most patients had 14-mm screws placed. Postoperative CT scanning showed no compromise of the foramen transversarium or neural foramen. A total of 94 C7 lateral mass screws were placed without the need for pedicle screws at this level. Forty-four cases were performed with a screw/plate construct with the remainder performed using a polyaxial screw/rod construct. One patient had a symptomatic adjacent-level disc herniation that required surgical intervention. One patient required extension of laminectomy for residual compression. CONCLUSIONS: Lateral mass screw fixation is a safe and effective stabilization technique. This study demonstrates the safety and efficacy of lateral mass cannulation for a range of cervical pathologies with the largest reported series of consecutive lateral mass screws in the literature. In most cases of subaxial disease, nonconstrained plate/screw systems provide a reasonable alternative to polyaxial screw/rod constructs. Most patients can be fixated with 14-mm length x 3.5-mm diameter screws. The C7 lateral mass can be drilled with an adjusted trajectory.

Adolescent↗

PubMed2003

Lateral septoaponeurotic artery: source of bleeding in blepharoplasty performed in asians.

In standard blepharoplasty, the orbital septum is opened commonly to enter the preaponeurotic space. This is to anchor the leading edge of the levator palpebral fascia to the skin of a proposed supratarsal fold and to remove supraorbital fat. Incision of the orbital septum is involved occasionally with accidental injury to an inconstant arterial branch at its lateral side, which causes severe bleeding. Anatomic knowledge of the vessel on the orbital septum is conducive to preventing accidental arterial injury. The authors encountered a relatively large artery running vertically at the lateral side of the orbital septum in 50 eyelids of 230 blepharoplasty patients (460 eyelids). They investigated the branch by injecting red latex into the ophthalmic arteries in 20 hemidissected faces of fresh cadavers. At the lateral aspect of the orbital septum, a branch of the superior lateral palpebral artery, which we named the lateral septoaponeurotic artery (LASA), was confirmed in five of 13 specimens. The LASA originates from the superior lateral palpebral artery just after it divides into peripheral and marginal arcades. The LASA pierces the levator aponeurosis and orbital septum at the upper level of the tarsal plate. It anastomoses with a branch of the supraorbital artery at the superior aspect of the orbit. The authors think severe bleeding occurs when the LASA is injured during blepharoplasties. Cautious treatment of the lateral septoaponeurotic vessel minimizes undesirable complications.

Arteries↗

PubMed2004

The extended SMAS facelift: identifying the lateral zygomaticus major muscle border using bony anatomic landmarks.

Extended superficial musculoaponeurotic system (SMAS) rhytidectomy has been advocated for improving nasolabial fold prominence. Extended subSMAS dissection requires release of the SMAS typically from the upper lateral border of the zygomaticus major muscle and continued dissection medial to this muscle. This maneuver releases the zygomatic retaining ligaments and achieves more effective mobilization and elevation of the ptotic malar soft tissues, resulting in more dramatic effacement of the nasolabial crease. Despite its presumed advantages, few reports have suggested greater risk of nerve injury with this technique compared with other limited sub-SMAS dissection techniques. Although the caudal extent of the zygomaticus muscle insertion to the modiolus of the mouth has been well delineated, the more cephalad origin has been vaguely defined. We attempted to define anatomic landmarks which could serve to more reliably identify the upper extent of the lateral zygomaticus major muscle border and more safely guide extended sub-SMAS dissections. Bilateral zygomaticus major muscles were identified in 13 cadaver heads with 4.0-power loupe magnification. Bony anatomic landmarks were identified that would predict the location of the lateral border of the zygomaticus major muscle. The upper extent of the lateral border of the zygomaticus major muscle was defined in relation to an oblique line extending from the mental protuberance to the notch defined at the most anterior-inferior aspect of the temporal fossa at the junction of the frontal process and temporal process of the zygomatic bone. The lateral border of the zygomaticus major muscle was observed 4.4 +/- 2.2 mm lateral and parallel to this line. More accurate prediction of the location of the upper extent of the lateral border of the zygomaticus major muscle using the above bony anatomic landmarks may limit nerve injury during SMAS dissections in extended SMAS rhytidectomy.

Cadaver↗