Publications by authors named "Siamak Yasmeh"

6 Publications

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Surgical management of humeral shaft nonunions. Success of a consistent protocol over 17 years.

Injury 2021 Apr 16. Epub 2021 Apr 16.

Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, USA.

Introduction: Surgical treatment of humeral shaft nonunions is characterized by variability of fixation methods, graft choices, and rates of union and iatrogenic radial nerve palsy. The aim of the current study is to evaluate the union rate of humeral shaft aseptic nonunions and the rate of postoperative complications following a consistent management protocol.

Patients And Methods: This is a retrospective review of 41 consecutive adult patients (23 female and 18 male with a mean age of 42 years) with aseptic nonunions of the humeral shaft treated by the senior author in our institution over a 17-year period. Nonunions were located in the middle third of the diaphysis in 33 patients, in the distal third in 6, and in the proximal third in 2 patients. Comorbidities were present in 49% of patients and the most common were smoking in 27% and diabetes mellitus in 17% of patients. Patients were treated at an average of 24 months after their injury. Surgical protocol consisted of careful dissection of the radial nerve, debridement of the nonunion site, stable plate fixation and augmentation of local biology.

Results: Thirty-eight patients had mean clinical and radiographic follow-up of 9.4 months. All 38 nonunions healed at a mean time of 3.5 months. There were no persistent nonunions and no failures of fixation. None of the 40 patients with an intact radial nerve preoperatively developed any signs of radial nerve compromise after surgery. Complications consisted of one superficial infection (2%) that resolved with oral antibiotics and one deep infection (2%) that required implant removal and debridement. The mean pain score on the visual analog scale was 0.7. Mean elbow range of motion was 125 degrees with a mean extension deficit of 5 degrees and mean flexion of 130 degrees.

Conclusions: Our surgical protocol achieved consistent healing of nonunions of the humeral shaft with a low complication rate and no iatrogenic radial nerve palsy, even in long-standing nonunions in patients with comorbidities.
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April 2021

Clinical and Radiographic Outcomes of Lateral Interbody Fusion for Adjacent Segment Degeneration.

Int J Spine Surg 2021 Feb 18;15(1):74-81. Epub 2021 Feb 18.

Department of Orthopedics and Rehabilitation, University of Wisconsin School of Medicine, Madison, Wisconsin.

Study Design: Retrospective cohort study.

Objective: Assessment of outcomes in patients undergoing lateral interbody fusion as part of the surgical treatment of adjacent segment deterioration after previous lumbar spine fusion.

Methods: Adult patients with previous lumbar posterior spinal fusion who presented with adjacent segment degeneration and stenosis refractory to nonoperative treatment and who underwent lateral lumbar interbody fusion were retrospectively analyzed. Clinical and radiographic outcomes were assessed and comparisons made between preoperative baseline and postoperative values.

Results: Thirty-six patients with symptomatic adjacent segment degeneration at 46 motion segments were included. Thirty (83.3%) of the 36 patients had complete relief of both preoperative lower extremity pain and back pain at the time of final follow-up. Six (16.7%) of the 36 patients had persistent pain, though in all 6 cases, the pain was less postoperatively than preoperatively. Oswestry Disability Index scores were improved significantly at final follow-up ( = .001). Compared with preoperative baseline parameters, initial and final postoperative radiographs had an increase in segmental lordosis ( < .001 and < .001, respectively), increase in overall lumbar lordosis ( < .05 and = .094, respectively), decrease in segmental coronal angulation ( = .63 and < .01, respectively), decrease in overall coronal angulation ( = .063 and = .009, respectively), and increase in intervertebral height ( < .001 and < .001, respectively).

Conclusion: Lateral lumbar interbody fusion achieves favorable clinical and radiographic outcomes for the treatment of adjacent segment degeneration after previous lumbar fusion.

Level Of Evidence: 4.
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February 2021

Firework-related hand injuries: A novel classification system.

Am J Emerg Med 2018 May 28;36(5):897-899. Epub 2017 Sep 28.

Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, United States.

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May 2018

Periosteal turndown flap for posterior occipitocervical fusion: a technique review.

Eur Spine J 2017 09 2;26(9):2303-2307. Epub 2017 May 2.

Children's Hospital Los Angeles, 4650 Sunset Blvd, MS#69, Los Angeles, CA, 90027, USA.

Purpose: Recently, several authors have proposed techniques for improving the fusion rate in pediatric posterior occipitocervical fusion including a variety of implants and the use of bone morphogenetic protein. A technique by Koop et al. using a periosteal flap for occipitocervical arthrodesis was described in 1984.

Methods: A straight incision is made about the posterior neck to expose the occipitocervical region from the inion superiorly to the lowest cervical vertebrae to be fused inferiorly. The occiput is exposed superficial to the periosteum, which is then reflected and elevated from the occiput. The attachment is preserved at the caudal base of the flap and reflected over the intended area of fusion. When possible, fixation is then performed with cables, wires, screws, hooks, or plates.

Case Example: A 6-year-old male with an occiput to C2 distraction injury underwent posterior spinal fusion from occiput to C3 using sublaminar wires, periosteal turndown flap, and autologous iliac crest bone graft.

Conclusion: In small children with traumatic upper cervical spine instability, the periosteal turndown technique may be used as a safe adjunct for occipitocervical fusions.
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September 2017

Walking activity during daily living in children with myelomeningocele.

Disabil Rehabil 2017 07 6;39(14):1422-1427. Epub 2016 Jul 6.

a Children's Orthopaedic Center, Children's Hospital Los Angeles , Los Angeles , CA , USA.

Purpose: To quantify the walking activity of children with myelomeningocele during daily living.

Method: Walking activity was measured using a StepWatch activity monitor over one week in 47 children with myelomeningocele (27 males; 9 years 11 months SD 2 years 7 months; 18 sacral, 9 low lumbar, 20 mid-high lumbar) and seven children with typical development (5 males; 11 years 1 month SD 1 year 11 months) in a prospective, cross-sectional study. Average total steps per day, number of steps and minutes spent at low, medium and high intensity stepping were evaluated. Groups were compared using t-tests and chi-squared tests with Bonferroni post-hoc adjustment.

Results: Children with sacral and low lumbar myelomeningocele exhibited no significant differences in demographic characteristics or walking performance compared to typically developing children. Children with mid-high lumbar myelomeningocele exhibited higher BMI percentile than the control group (p = 0.04) and took fewer total steps per day than all other groups (p ≤ 0.04). Children with mid-high lumbar myelomeningocele also spent significantly less time taking steps at all intensity levels, particularly medium-intensity, than the sacral and low lumbar groups (p ≤ 0.04).

Conclusions: Children with sacral and low lumbar myelomeningocele had walking performance similar to typically developing children despite a common need for braces and assistive devices. Children with mid-high lumbar myelomeningocele were less active, which may lead to heightened risk for secondary health conditions in addition to those associated with myelomeningocele. Implications for Rehabilitation Obesity, muscle weakening and disuse osteoporosis are issues for those with myelomeningocele, all of which are affected by walking activity. Understanding walking activity and intensity in children and adolescents with myelomeningocele may aid in developing focused rehabilitation interventions and strategies. Real world walking activity as an objective and quantified measure has the potential to help guide therapists and surgeons to more effective treatments.
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July 2017

Repeat hamstring lengthening for crouch gait in children with cerebral palsy.

J Pediatr Orthop 2013 Jul-Aug;33(5):501-4

Children's Orthopaedic Center, Children's Hospital Los Angeles, Los Angeles, CA 90027, USA.

Background: Progressive crouch gait occurs in patients with cerebral palsy with increasing age. Hamstring lengthening improves crouch in these patients, but hamstring contractures can recur over time. The purpose of this study was to determine whether revision hamstring lengthening is as effective as primary lengthening in improving crouched gait.

Methods: Retrospective review was performed for 39 patients with static encephalopathy, average age 10±4 years, who underwent hamstring lengthening. Twenty-one subjects underwent a single hamstring lengthening (HSL group), and 18 underwent repeat HSL (rHSL group). Range of motion (ROM) and kinematic measures from preoperative and postoperative gait analysis testing were compared within and between groups using t tests, χ2 tests, and multiple regression analyses as appropriate.

Results: A total of 15/21 subjects in the HSL group (71%) improved stance knee extension by ≥10 degrees, as compared with 5/18 (28%) in the rHSL group (P=0.007). The HSL group had improved popliteal angle, static knee and hip extension ROM, and knee flexion at initial contact and in stance phase (P<0.003). No such improvements were seen in the rHSL group. Popliteal angle, knee and hip extension ROM, and knee flexion at initial contact and in stance phase had significantly greater improvement in the HSL than the rHSL group (P<0.01). These differences persisted after adjusting for preoperative minimum hip flexion in stance, the only variable that differed between groups preoperatively.

Conclusions: Repeat hamstring lengthening may delay progressive crouch, but does not result in long-term correction of crouch gait. Recurrent crouch may be caused by other factors such as quadriceps insufficiency, and may reflect the natural history of CP. Patients with recurrent crouch after hamstring lengthening are likely to benefit more from alternative surgical interventions to improve their knee position and function during gait.

Level Of Evidence: Level IV-case series.
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February 2014