Middle Thoracic Segments Research Articles

Localization of rib fractures following blunt thorax trauma and investigating the relationship between these and traumatic hemopneumothorax

Background: Thorax traumas form 20-25% of deaths resulting from trauma. In the young population, the most common reason for death resulting from trauma is thorax trauma. The investigation of blunt thorax trauma reveals that the most common reason in the young population is 'in-vehicle motor traffic accidents (IVMTA), while falls take the 1st place in the geriatric population. The relationship between the localization of rib fractures developing due to blunt thorax trauma and the resultant hemothorax, pneumothorax, or hemopneumothorax investigated, and results compared. Material and Method: Between the dates November 2018 and November 2019, thoracic computerized tomography views of a total of 81 patients who applied with blunt thorax trauma and rib fractures evaluated retrospectively. Rib fractures were divided into three as upper, middle and lower thoracic segments according to their localization. Results: The most common localization for rib fracture was the middle thoracic segment with 57 (70.3%) patients. The mean hospitalization period was 5.4 (range: 1-24) days. Additional pathological findings were hemothorax, pneumothorax, and hemopneumothorax in 20 (24.7%), 16 (19.8%), and 5 (6.2%) patients, respectively. Among thoracic segments where rib fractures encountered, the upper thoracic segment most commonly led to hemothorax and pneumothorax with 11 (32.3%) and 8 (23.5%) patients, respectively. Conclusion: The most common localization of rib fractures following blunt thorax trauma is the upper and middle thoracic segment. In the upper thoracic segment, emergency thorax surgery complications like hemothorax/pneumothorax follow posttraumatic rib fractures in the earlier term and are more common when compared to other segments. The segmental localization of rib fractures developing due to blunt thorax trauma is essential in terms of morbidities, and the decision of invasive or conservative treatment depends on this information.

A comparative study of three-dimensional, four-dimensional, and cone beam contrast-enhanced computed tomography in measurement of the normal thickness of the esophageal wall

Objective To compare the normal thickness of the esophageal wall measured by contrast-enhanced three-dimensional (3DCT), four-dimensional (4DCT), and cone beam computed tomography (CBCT), and to provide a basis for target volume delineation in esophageal cancer. Methods From 2009 to 2016, thoracic contrast-enhanced 3DCT and 4DCT simulations were performed in 50 patients with lung cancer or metastatic lung cancer. Contrast-enhanced CBCT scans were acquired during the first three-dimensional conformal radiotherapy. The normal esophageal wall was contoured on 3DCT images, the end-exhalation phase of 4DCT images (4DCT50), the maximum intensity projection of 4DCT images (4DCTMIP), and CBCT images. The wall thickness was measured on each segment and the average thickness of esophageal wall was obtained. Comparison of the thickness of a fixed segment of esophageal wall between different CT images was made by paired t test. Comparison of thickness on the same type of CT images between different segments of esophageal wall was made by one-way analysis of variance. Results For the thoracic and intra-abdominal segments, there was no significant difference in the thickness of esophageal wall between 3DCT and 4DCT50 images (P=0.056-0.550); however, the thickness of esophageal wall was significantly smaller on 3DCT images than on 4DCTMIP or CBCT images (P=0.000-0.004). For the upper and middle thoracic segments, the thickness of esophageal wall was significantly larger on CBCT images than on 4DCTMIP images (P=0.008, P=0.001). On 3DCT, 4DCT50, and 4DCTMIP images, the thickness of esophageal wall was significantly larger in the lower thoracic segment than in the upper or middle thoracic segments (P=0.008~0.041); the intra-abdominal segment had a significantly larger thickness of esophageal wall than the thoracic segments (all P=0.000). There was no significant difference in wall thickness on CBCT images between three thoracic segments (P=0.088~0.945). Conclusions A uniform criterion can be adopted to judge the normal thickness of esophageal wall in gross tumor volume (GTV) delineation on 3DCT and 4DCT50 images for thoracic esophageal cancer. However, caution should be taken when 5 mm is used as a criterion for normal thickness of esophageal wall in GTV delineation on 4DCTMIP and CBCT images. Key words: Tomography, X-ray computed, three-dimensional; Tomography, X-ray computed, four-dimensional; Tomography, X-ray computed, cone beam; Normal oesophagus; Wall thickness

A New Record of the Genus Pista (Polychaeta: Terebellidae) from Korea: The Validity and Redescription of Pista shizugawaensis

A terebellid polychaete identified as Pista shizugawaensis Nishi and Tanaka, 2006, whose species validity has been doubted, is newly reported from the southwest coast of Korea. Korean materials of the present study have several characteristics that agree well with the original description of P. shizugawaensis as follows: two pairs of branchiae on the 2nd and 3rd segments have tufts composed of many dichotomously branched filaments; the nephridial papillae are present on the 6th and 7th segments; the uncini on the anterior and middle thoracic segments possess only long-handled shafts while those on the posterior ones have additional short-handled shafts or lacking shafts; the notosetae are broadly or narrowly winged capillary. The authors examined the taxonomic value of the presence of lateral lobes on the 5th and 6th segments, which has been known as a key characteristic feature of P. shizugawaensis in the classification of Pista species. In the present study, several characteristics such as the shape of notosetae, uncinial shafts in the thoracic segments, and the presence of thin narrow lateral lobes on the 4th segment are suggested as the specific characteristics that help to distinguish P. shizugawaensis from its congeners. A key to Pista species from Korean waters is also provided.

Kinematics of the Thoracic Spine in Trunk Rotation

In vivo 3-dimensional (3D) study of the thoracic spine. To demonstrate axial rotations (ARs) and coupled motions of the thoracic spine. In vivo 3D kinematics of the thoracic spine in trunk rotation with intact thorax and soft tissues has not been well-known.There were no quantitative data of AR in the consecutive thoracic spinal segments. Patterns of coupled motion with AR have been controversial. Thirteen healthy volunteers underwent 3D computed tomography of the thoracic spine in 3 positions; neutral, right, and left maximum trunk rotation. Relative motions of vertebrae were calculated by automatically superimposing the vertebrae in a neutral position over images in rotational positions, using voxel-based registration. Motions were represented with 6 degrees of freedom by Euler angles and translations on the local coordinate system. Mean (± SD) relative rotational angles of T1 with respect to L1 to 1 side were 24.9° ± 4.9° in maximum trunk rotation. AR of each thoracic segment with respect to the inferior adjacent vertebra to 1 side was 1.2° ± 0.8° at T1-T2, 1.6° ± 0.7° at T2-T3, 1.4° ± 0.9° at T3-T4, 1.6° ± 0.8° at T4-T5, 1.8° ± 0.7° at T5-T6, 1.9° ± 0.6° at T6-T7, 2.3° ± 0.7° at T7-T8, 2.5° ± 0.8° at T8-T9, 2.7° ± 0.6° at T9-T10, 2.6° ± 0.8° at T10-T11, 1.3° ± 0.7° at T11-T12, and 0.5° ± 0.4° at T12-L1. Significantly larger segmental AR was observed at the middle thoracic segments (T6-T11) than at the upper (T1-T6) and lower (T11-L1) segments. At the upper thoracic segments, coupled lateral bending with AR was observed in the same direction as AR. However, at the middle and lower thoracic segments, coupled lateral bending occurred both in the same and opposite directions. In vivo 3D ARs and coupled motions of the consecutive thoracic spinal segments in trunk rotation were investigated accurately for the first time.

Thoracic Pedicle Morphometry in Different Body Height Population

A three-dimensional study of the thoracic pedicle (T1-T12) morphometry in Chinese patients with different body height, using reformatted computed tomography (CT). To quantify the dimensions of the thoracic pedicles and to analyze the relationship between body height and thoracic pedicle parameters. The thoracic pedicle morphometry has been studied extensively in different populations using various techniques. Previous studies have shown a significantly smaller size of the thoracic pedicles in women than in men and in Asians than in Caucasians. Some authors postulated that it is the body height that contributes to the variation in the pedicle size. To our knowledge, however, no study has specifically analyzed the relationship between body height and thoracic pedicle parameters in detail. In this study, T1 to T12 vertebrae were imaged in 126 Chinese patients by a Lightspeed Vct CT (General Electric, Bridgeport, Connecticut, USA). After reformatting the original images, the following parameters were calculated: outer pedicle width, outer pedicle height and pedicle cortical thickness of the pedicle isthmus, pedicle length, and transverse pedicle angle. All measured data were statistically analyzed by the independent t test and Pearson correlation test using SPSS software (SPSS Inc, Chicago, IL). The thoracic pedicle parameters were significantly smaller in women than in men except for the transverse pedicle angles and the pedicle cortical thickness. The percentage of outer pedicle widths less than 4.5 mm was extremely high at T3 to T9 in females and T4 to T7 in males. There was a much higher percentage of pedicle width of 4.5 mm or lesser, 4.0 mm or lesser, and 3.5 mm or lesser when body height was less than 160 cm. Body height is probably one of the main factors that contribute to the variation in pedicle size since a significant positive correlation was observed between pedicle size and body height. Body height is probably one of the main factors that contribute to the variation in pedicle size among different ethnic and sex groups. Transpedicular procedures using a 4.5-mm screw may not be applicable to much of the Chinese population at the upper and middle thoracic segments, especially for patients less than 160 cm in height. A reformatted CT evaluation is routinely recommended not only for choosing the proper screw but also for determining the feasibility of a true transpedicular procedure.

Thoracic discectomy via trans-facet-joint approach

Objective To evaluate the clinical effect of thoracic discectomy via trans-facet-joint approach in the treatment of thoracic disc herniation.Methods Thirty-three cases were included in this group from October 1994 to August 2009.There were 27 males and 6 females.The age ranged from 18 to 72 years old,with an average of 41.8 years.The course of disease ranged from 12 days to 36 months and was lesser than one month in 13 cases.The weakness and numbness of lower limbs occurred after trauma in 9 cases.Fifteen cases were diagnosed as simple thoracic disc herniation.Six cases were associated with ossification of posterior longitudinal ligament and 12 cases were associated with ossification or hypertrophy of yellow ligament.A total of 45 discs were involved,including 32 in lower thoracic segments(71.11%),8 in upper thoracic segments(17.78%)and 5 in middle thoracic segments(11.11%).All the herniated discs and the ossified OPLL were excised via the trans-facet-joint approach.For the cases with ossification or hypertrophy of yellow ligament,the laminectomy and replantation were performed.The screw-rod system was used on both sides in 14 cases,on one side in 19 cases.Results Follow-up was acquired in 27 patients,ranged from 12 to 63 months(mean,37 months).According to Epstein and Schwall grade,there were excellent in 15 cases,good in 10 cases,improved in 2 cases and poor in 2 cases.The excellent and good rate was 86.21% and total effective rate was 93.10%.Postoperative complications occurred in 3 cases,including exacerbation of preexisting deficits in 2 cases and implant failure in 1 case.The former 2 cases were treated with methylprednisolone,dehydrant,neural nutrition and hyperbaric oxygen.One patient had recovered to preoperative level,the other had not recovered to the preoperative level.The implant was removed 18 months after operation for the implant failure.The post-operative CT or MRI showed that all the replanted lamina obtained fusion,and the canal decompression was complete.Conclusion Thoracic discectomy via trans-facet-joint approach can improve the clinical result obviously. Key words: Thoracic vertebrae; Spinal stenosis; Intervertebral disk displacement; Diskectomy

Activity of the intercostal muscle spindle afferents in the lower thoracic segments during spontaneous breathing in the cat

Intraaxonal recordings of 33 spindle afferents from the inspiratory ( n = 8) and expiratory ( n = 25) intercostal muscles in the lower thoracic segments (T9-11), were made during spontaneous breathing in the anesthetized cat. All of them showed respiration-related activity. However, only three spindle afferents (one from the inspiratory and two from the expiratory intercostal muscles) showed higher firing frequency during the active contraction phase of the receptor-bearing muscle. The remaining 30 spindle afferents (seven from the inspiratory and 23 from the expiratory muscles) showed the maximum firing discharge during the passive stretch phase of the parent muscles. On the other hand, in the middle thoracic segments (T6-7), five of six spindle afferents from the inspiratory muscles and four of nine spindle afferents from the expiratory muscles showed maximum firing rate during parent muscle contraction in agreement with previous study. These results suggest that the spindle activity in the lower thoracic segments is dominated by muscle length changes, whereas that in the middle thoracic segments is largely via the fusimotor pathway.

Spinocerebellar projections from the thoracic cord in the cat, as studied by anterograde transport of wheat germ agglutinin-horseradish peroxidase.

The projection fields of the spinocerebellar tracts arising from thoracic segments were studied by the anterograde transport of wheat germ agglutinin bound to horseradish peroxidase (WGA-HRP) in the cat. Following injections of WGA-HRP into upper and middle thoracic segments, labeled mossy fiber terminals were seen in all lobules of the anterior lobe, lobules VI, VIII, and IX, soblobule VIIb, the paramedian lobule, medial parts of the dorsal paraflocculus, crus I, crus II, and the simple lobule. In the anterior lobe labeled terminals in sublobules IIb-Vb accounted for about 50-60% of the total labeled terminals, of which about 14-18% were present in lobule III and 11-13% were present in lobule IV. The labeled terminals were concentrated within 1.0-1.5 mm from the midline in the vermal region, accounting for about 45-75% of the total in each sublobule. Following injections into lower thoracic segments, labeled terminals tended to distribute more numerously in the lateral part of the vermis and the intermediate region. In the posterior lobe about 5% of the total labeled terminals were distributed in lobules VI and VIII, respectively, and about 16-23% were in the paramedian lobule (mainly sublobules B and C). Cases with injections preceded by a lateral cordotomy have shown that about 65% of the total labeled terminals in each lobule of the anterior lobe were distributed ipsilaterally and 35%, contralaterally. In the paramedian lobule the labeled terminals were distributed predominantly ipsilaterally. Projection fields in the horizontal plane were reconstructed from a series of transverse sections through each lobule. In lobules III and IV the labeled terminals were distributed in nine areas: areas 1-4 in the vermis and areas 5-9 in the intermediate-lateral regions. The two medial areas 1 and 2 were located within 0.5 mm from the midline in zone A1 of Voogd and area 3 appeared to be located in zone A2. Area 4 was located between 0.75 and 1.5 mm in the medial part of zone B. These areas extended longitudinally in the middle part of the apicobasal extent. The five areas in the intermediate-lateral regions were localized in the basal part of the lobule: area 5 in zone C1, areas 6-8 in zones C2 and C3, and area 9 in zone D. Some of these projection areas were identified also in lobules I, II, and V.(ABSTRACT TRUNCATED AT 400 WORDS)

Intraspinal arachnoiditis and hydrocephalus after lumbar myelography using methylglucamine iocarmate.

A 35 year old woman developed a severe meningeal reaction after lumbar myelography using the water-soluble contrast medium methylglucamine iocarmate. Three months after myelography the findings were a transverse spinal cord syndrome corresponding to the middle thoracic segments resulting from well developed leptomeningeal adhesions. This was combined with a noncommunicating hydrocephalus, probably the result of leptomeningeal fibrosis in the posterior fossa. After treatment with a ventriculoatrial shunt the patient is almost free of symptoms. A possible pathogenetic relationship between the contrast medium, the chronic leptomeningeal changes, and the symptoms of our patient is discussed on the basis of the literature.

Extra-segmental reflexes derived from intercostal afferents: phrenic and laryngeal responses.

1. Phrenic and recurrent laryngeal efferent responses were evoked by brief tetani or single shocks to the cut external intercostal nerves of anaesthetized cats. The reflexes derived from middle thoracic segments (T5 and 6) were compared with those emanating from caudal thoracic segments (T9 and 10).2. During inspiration, middle intercostal nerve stimulation transiently inhibited the spontaneous discharge in both efferent neurograms, whereas stimulation of caudal intercostal nerves facilitated phrenic discharge and usually inhibited recurrent laryngeal activity.3. During expiration, stimulation at either thoracic level enhanced recurrent laryngeal discharge while provoking little or no phrenic response.4. Superficial lesions of the lateral cervical cord, ipsilateral to the stimulus sites, above or below the phrenic outflow, eliminated all reflex responses except the phrenic response to caudal thoracic stimuli. Similarly, in the spinal animal, middle intercostal afferents could not be shown to decrease phrenic excitability. Caudal intercostal afferents cause phrenic excitation by a spinal reflex.5. Group I afferents of the mid-thoracic segments and group II afferents of the caudal thoracic segments initiate these extra-segmental reflexes.6. The recurrent laryngeal responses manifest, for the most part, changes in the discharge of fibres innervating the posterior cricoarytenoid muscle. The responses fit the overall pattern of response to middle intercostal nerve stimulation, namely, inhibition of inspiratory muscles and excitation of expiratory muscles. Intercostal afferent stimulation also activated the laryngeal adductor muscles.7. The results support the view that intercostal mechanoreceptors initiate an array of extra-segmental respiratory reflexes, including spinal and supraspinal arcs. The simplest way to account for the various responses to stimulation of middle intercostal afferents is to postulate a reflex involving supraspinal respiratory neurones.8. The observed reflexogenic differences correlate with anatomical differences between the middle and caudal ribs. Possible functional implications of this relationship are discussed.