Mylohyoid Muscle: Current Understanding for Clinical Management-Part I: Anatomy and Embryology.

The mylohyoid is one of the suprahyoid muscles, along with the geniohyoid, digastric, and stylohyoid muscles. It lies between the anterior belly of the digastric muscle inferiorly and the geniohyoid superiorly. In Part I, the anatomy and embryology of the mylohyoid muscle will be reviewed in preparation for the clinical discussion in Part II.

Cervical osteochondroma with neurological symptoms: literature review and a case report.

INTRODUCTION: Osteochondromas are common benign tumors of bone and spinal involvement is uncommon. Solitary spinal osteochondromas may produce a wide variety of symptoms depending on their location and relationship to adjacent neural structures. CASE PRESENTATION: Herein, we present a case of solitary osteochondroma arising from the posterior arch of C1, causing left-sided ascending numbness and paresthesia and difficulty walking. The lesion was totally resected through a posterior approach. Histopathological examination confirmed the diagnosis of benign osteochondroma. DISCUSSION: Spinal cord compression is uncommon in spinal osteochondromas because in most cases the tumor grows out of the spinal column. To prevent neurological compromise, complete surgical removal is mandatory when an intraspinal osteochondroma with cord compression is diagnosed, which also helps to prevent recurrence. Our literature review of similar cases indicates that despite the old belief that C2 is the most commonly involved vertebra for osteochondromas, C1 is actually the most commonly involved vertebra in the cervical region.

Association Between Allogeneic Blood Transfusion and Postoperative Infection in Major Spine Surgery.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective of this study is to compare the incidence of infection in patients who do and do not receive blood transfusions in major deformity surgery (>8 levels). SUMMARY OF BACKGROUND DATA: Postoperative infections increase morbidity and mortality rates in spine surgery and generate additional costs for the health care system. It has been proposed that blood transfusions increase the risk of wound infection, urinary tract infection, pneumonia, and sepsis. METHODS: A total of 56 patients met the study criteria, receiving spine surgery involving the fusion of 8 levels or more. Patient-specific characteristics, starting and ending hematocrits, number of units transfused and infections including urinary tract infection, wound infection, pneumonia, and sepsis were documented. Differences in infection risk between those who did and did not undergo a transfusion and their 95% confidence intervals were calculated. RESULTS: Groups were similar with respect to baseline and surgical characteristics except for smoking status, operative time, estimated blood loss, and ending hematocrit. The overall infection rate was greater in patients who underwent transfusion than those who did not (36% vs. 10%; P=0.03). Wound infections (n=5) were only observed in those who underwent a transfusion. Smokers were more likely to receive a transfusion and more likely to experience infection. A stratified analysis demonstrated an increased risk of infection associated with transfusion; however, the risk was greater in smokers, suggesting the effect of transfusion on infection could be modified by smoking. Patients undergoing transfusion experienced a significantly longer hospital stay (P=0.01). CONCLUSIONS: Allogeneic red blood cell transfusion in major spine surgery could be a risk factor for postoperative infection. This increased risk seems to be magnified in those who smoke. Further studies are warranted, and risks of blood loss and transfusion-related complications in smokers also potentially merit exploration. LEVEL OF EVIDENCE: Level 3.

Relationship of dorsal root ganglion to intervertebral foramen in lumbar region: an anatomical study and review of literature.

BACKGROUND: The purpose of this study was to clarify the morphologic features, location and variations of the dorsal root ganglion (DRG). METHODS: Fifteen formalin fixed cadavers for the current study were included. Total of 150 DRGs were examined from L1 to L5. The relationships of the nerve root DRGs to the intervertebral foramen were noted. Position of the DRG was classified by the location of the ganglia in relation to the pedicle. The relationship of the DRG to the intervertebral foramen was evaluated. RESULTS: The distance between the midpoint of the DRG to the cross section of the root with the medial border of the pedicle gradually increased from L1 to L5. The medial border of the foramen distances along the nerve root were L1, 1.77 mm; L2, 2.79 mm; L3, 3.23 mm; L4, 7.28 mm and L5, 8.31 mm. The mean width of the lumbar DRGs were L1, 4.36 mm; L2, 4.56 mm; L3, 4.99 mm; L4, 5.22 mm and L5, 5.82 mm. The mean length of DRGs were as follows: L1, 5.39 mm; L2, 5.83 mm; L3, 7.24 mm; L4, 7.97 mm and L5, 10.83 mm. The mean width and length of DRGs gradually increased from L1 to L5. CONCLUSIONS: The DRG in the lumbar region play a key role in the occurence of low-back pain and sciatica; therefore, it is important to understand the anatomy of DRG. The accurate anatomic information about the position of DRGs would be useful to perform a safe surgical intervention in the lumbar foraminal region.

Virtual interactive presence and augmented reality (VIPAR) for remote surgical assistance.

BACKGROUND: Surgery is a highly technical field that combines continuous decision-making with the coordination of spatiovisual tasks. OBJECTIVE: We designed a virtual interactive presence and augmented reality (VIPAR) platform that allows a remote surgeon to deliver real-time virtual assistance to a local surgeon, over a standard Internet connection. METHODS: The VIPAR system consisted of a "local" and a "remote" station, each situated over a surgical field and a blue screen, respectively. Each station was equipped with a digital viewpiece, composed of 2 cameras for stereoscopic capture, and a high-definition viewer displaying a virtual field. The virtual field was created by digitally compositing selected elements within the remote field into the local field. The viewpieces were controlled by workstations mutually connected by the Internet, allowing virtual remote interaction in real time. Digital renderings derived from volumetric MRI were added to the virtual field to augment the surgeon's reality. For demonstration, a fixed-formalin cadaver head and neck were obtained, and a carotid endarterectomy (CEA) and pterional craniotomy were performed under the VIPAR system. RESULTS: The VIPAR system allowed for real-time, virtual interaction between a local (resident) and remote (attending) surgeon. In both carotid and pterional dissections, major anatomic structures were visualized and identified. Virtual interaction permitted remote instruction for the local surgeon, and MRI augmentation provided spatial guidance to both surgeons. Camera resolution, color contrast, time lag, and depth perception were identified as technical issues requiring further optimization. CONCLUSION: Virtual interactive presence and augmented reality provide a novel platform for remote surgical assistance, with multiple applications in surgical training and remote expert assistance.