Biomedical subjects

Mohammad Diab

Publications and source records attributed to Mohammad Diab.

7 recordsLinked to original sources

PubMed2006

A biomechanical analysis of sublaminar and subtransverse process fixation using metal wires and polyethylene cables.

STUDY DESIGN: An in vitro biomechanical calf thoracic spine study. OBJECTIVE: To evaluate the biomechanical stability of sublaminar and subtransverse process fixation using stainless steel wires and ultra-high molecular weight polyethylene (UHMWPE) cables. SUMMARY OF BACKGROUND DATA: It is commonly held that transverse process fixation provides less stability than sublaminar fixation. To our knowledge, this is the first biomechanical study to compare the stability afforded by sublaminar fixation and subtransverse process fixation using metal wire and UHMWPE cable before and after cyclic loading. METHODS: There were 6 fresh-frozen calf thoracic spines (T4-T9) used to determine the sublaminar fixation stiffness and subtransverse process fixation stiffness in each group. Double strands of 18-gauge stainless steel wire, 3 and 5 mm-width UHMWPE cable (Nesplon; Alfresa, Inc., Osaka, Japan) were applied to each spine. Cyclic pure flexion-extension moment loading (2 Nm, 0.5 Hz, 5000 cycles) was applied after the initial stability was analyzed by measuring the range of motion. Statistical analyses were used to delineate differences between the various experimental groups. RESULTS: Subtransverse process wiring was more stable than sublaminar wiring after cyclic loading in flexion-extension (P < 0.05). There were no significant differences between each group in lateral bending and axial rotation after cyclic loading. Sublaminar stainless steel wiring was more stable than sublaminar 3 and 5-mm cable before and after cyclic loading in axial rotation (P < 0.01). Acute subtransverse process fixation using 3-mm cable was less stable after cyclic loading in axial rotation (P < 0.05). All other groups did not produce statistically significant differences. CONCLUSIONS: Subtransverse process fixation provides at least as much stability as sublaminar fixation. A 5-mm UHMWPE cable and stainless steel wire result in equivalent sublaminar and subtransverse process stability.

Animals↗

PubMed2006

Osteotomy does not improve early outcome after slipped capital femoral epiphysis.

We performed a retrospective, nonrandomized cohort study of unilateral, chronic, severe, stable slipped capital femoral epiphysis comparing five girls and five boys who underwent in-situ screw fixation alone with five girls and five boys who underwent in-situ screw fixation combined with staged flexion intertrochanteric femoral osteotomy to restore proximal femoral alignment. Functional outcome was measured by the Harris hip score, with 20% selected as a goal for improvement in functional outcome after corrective osteotomy. While flexion intertrochanteric femoral osteotomy improved hip range of motion, we found no significant difference in functional outcome between the two groups at early follow-up. This is a level 3 evidence study.

Adolescent↗

PubMed2006

The effect of age on motor evoked potentials in children under propofol/isoflurane anesthesia.

Intraoperative transcranial motor evoked potential (MEP) monitoring may help prevent neurologic injury during spine surgery. This type of monitoring may be difficult in the pediatric population under general anesthesia. We retrospectively reviewed data from 56 children, aged 2 to 18 yr, who were to undergo surgical correction of idiopathic scoliosis with MEP monitoring. Under combined isoflurane-propofol general anesthesia, before incision, we examined the minimum stimulating threshold voltage required to achieve a 50-microvolt or greater MEP response amplitude. Younger age was associated with an increase in the threshold voltage needed to elicit a sufficient MEP response. In addition, younger age was associated with longer stimulating pulse trains and greater need to adjust stimulating scalp electrodes. Body surface area, height, weight, and body mass index were also significant factors, but they were not independent predictors, after adjusting for age. Younger children received significantly lower levels of isoflurane and comparable doses of propofol, compared with older patients. Stronger stimulation needed to produce MEP responses in younger patients may reflect immaturity of their central nervous system, specifically conduction by the descending corticospinal motor tracts. Greater attention must be given to optimizing physiologic variables, limiting depressant anesthetics, and selecting the most favorable stimulating conditions in children, especially those <10 yr old.

Adolescent↗

PubMed2005

Scapulothoracic fusion for facioscapulohumeral muscular dystrophy.

BACKGROUND: Facioscapulohumeral muscular dystrophy causes winging of the scapula and weakness and discomfort of the shoulder. Surgical stabilization of the scapula to the posterior part of the chest wall permits shoulder abduction and flexion by the deltoid muscle. In the present retrospective study, we describe our experience with eleven scapulothoracic fusion procedures that were performed for the treatment of the infantile and adolescent forms of the disease. METHODS: Eleven procedures were performed in eight patients, including four male patients (one of whom had bilateral involvement and three of whom had unilateral involvement) and four female patients (two of whom had bilateral involvement and two of whom had unilateral involvement). One of the female patients had the infantile variant, whereas all other patients had the adolescent form of the disease. The mean age at the time of the eleven operations was seventeen years. The scapula was fused to the thorax in 25 degrees of abduction with use of 16-gauge wires, a plate or washers on the posteromedial scapular surface to prevent wire pull-out, and iliac crest autograft. After a mean duration of follow-up of 6.3 years, all patients were assessed clinically and radiographically. RESULTS: In all cases, scapular winging and shoulder fatigue and pain were initially eliminated. In the first year after the operation, active abduction and flexion of the shoulder improved to a mean of 145 degrees (range, 110 degrees to 160 degrees ) and 144 degrees (range, 130 degrees to 160 degrees ), respectively, from a preoperative mean of 75 degrees (range, 70 degrees to 90 degrees ). At the time of the final assessment (mean, 6.3 years postoperatively), abduction and flexion were maintained at a mean of 139 degrees and 134 degrees , respectively, in seven shoulders; however, in the remaining four shoulders, both of these motions had decreased to a mean of 48 degrees because of progressive loss of deltoid muscle strength. In two cases, prominent subcutaneous wires required trimming. There were no other complications. CONCLUSIONS: Scapulothoracic fusion relieves shoulder fatigue and pain, allows for smooth functional abduction and flexion of the upper extremity, and improves the appearance of the neck and shoulder in patients who have symptomatic scapular winging due to facioscapulohumeral muscular dystrophy. The procedure is associated with a low risk of complications. Progression of the disease affecting the deltoid muscle can cause loss of abduction, but the other benefits of stabilization persist. LEVEL OF EVIDENCE: Therapeutic Level IV.

Adolescent↗

PubMed2004

Intertrochanteric versus subcapital osteotomy in slipped capital femoral epiphysis.

We reviewed 15 flexion intertrochanteric osteotomies and 11 subcapital osteotomies done for chronic, severe, stable slipped capital femoral epiphysis at one institution with a minimum 2 years followup. The goal was to determine which procedure achieved better deformity correction and which procedure was safer. Radiographically, the two groups were equivalent in compensating for epiphyseal slip. Flexion intertrochanteric osteotomy was more effective in restoring proximal femoral anatomy, as determined by articulotrochanteric distance and trochanter-center of head distance. The incidence of complications, including osteonecrosis and chondrolysis, was low for both groups, but the reoperation rate was greater in the subcapital osteotomy group than in the flexion intertrochanteric group. Flexion intertrochanteric osteotomy seems to be an effective, safe, and reproducible realignment osteotomy for treatment of chronic, severe, stable slipped capital femoral epiphysis.

Adolescent↗

PubMed2003

Osseous fragility in Marshall-Smith syndrome.

Marshall-Smith syndrome is characterized by accelerated osseous maturation, craniofacial anomalies, failure to thrive, psychomotor delay, hypotonia, pulmonary dysfunction, and limited life expectancy. We describe a 7-year-old girl who, in addition to meeting these criteria for Marshall-Smith syndrome, had multiple fractures and skeletal anomalies. The purpose of this report is to draw attention to Marshall-Smith syndrome as one of the skeletal dysplasias characterized by osseous fragility.

Age Determination by Skeleton↗

PubMedDate not supplied

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Humans↗