ABSTRACT
Objective To measure the circumferential cortical thickness of anterior entrance and anterior half of lower cervical pedicles on computed tomography (CT) images, providing a reference for accurate anterior cervical pedicle screws. Methods CT scanning was performed in 10 normal lower cervical vertebrae from fresh cadavers, and the coronal and sagittal reconstructed images were obtained. The images were then opened in AutoCAD-2007 software to perform quantitative measurement (accuracy was 0. 1 mm) using the “dimaligned function” of dimension menu, and measurement parameters included the thicknesses of superior, medial, inferior and lateral cortex of anterior entrance of pedicle (SAE. MAE. IAE and LAE. respectively), and thicknesses of superior, medial, inferior and lateral cortex of anterior half of pedicle (SPA, MPA, IPA and LPA, respectively). Results Average thicknesses of SAE. MAE. IAE. LAE, SPA, MPA. IPA, and LPA at left and right side from Q to C7 were (1. 9 + 0. 6) and (1. 9 + 0. 5) mm, (1. 9 + 0. 7) and (1.9+0. 4) mm. (2.4 + 0. 6) and (2. 4 + 0. 5) mm, (0. 9 + 0. 5) and (0. 9 + 0. 6) mm, (2. 3 + 0. 9) and (2. 3 +0. 7) mm, (2. 1 + 0. 5) and (2. 1 + 0. 6) mm, (2. 2+0. 8) and (2. 2+0. 7) mm, and (1. 0 + 0. 7) and (1. 0 + 0. 6) mm, respectively. There was no significant difference in same measurement parameter between left and right sides at same cervical level (P>0. 05). Single factor random block analysis of variance found LAE and LPA were significantly thinner than the other 6 parameters of the same side of same cervical vertebra (all P0. 05). Conclusion LAE and LPA are the thinnest among the 8 measurement parameters from C3 to C7, which suggests LAE and LPA have the weakest resistance to exotic force if resistance strength to exotic force is parallel to cortex thickness. We should avoid locating close to LAE when finding anterior entrance or close to LPA when inserting anterior cervical pedicle screws.
ABSTRACT
Objective:A patient with L3-5 lumbar disc herniations and right spinal recess stenosis at L4-5 level associated with type IIB lumbosacral nerve anomaly(LSNA) at right side according to Neidre and Macnab classification system missed preoperatively and initially misdiagnosed as type IIA intraoperatively was reported. The reasons leading to missed diagnosis preoperatively and misdiagnoses intraoperatively were analyzed. Methods: A 62-year-old female was admitted to our hospital for intermittent radiating pain and claudication to the right lower extremity for about 20 years, radiating pain to the left lower extremity for 2 weeks. Physical examination found the left L5 nerve and right L4 and L5 nerves were impinged. CT and MR scannings revealed L3-4 disc herniation at right side, L4-5 disc herniation at central and left side with severe lateral recess stenosis at right L4-5 level. Image examinations failed to find a nerve root anomaly preoperatively. Following failed conservative treatment, the patient accepted decompression operation initially at left side. Left L5 nerve compressed by the herniated L4-5 disc was found firstly, which was liberated by discectomy. When doing decompression exploration at right side, it was found that two lumbar nerve roots exited L4-5 intervertebral foramen while the upper one was compressed by the herniated L3-4 disc which was liberated by discectomy and the lower one was free of compression. With exposing the right side and partly unroofing of stenosed right L4-5 lateral recess, no typical L5 nerve root was found passing over the posterior surface of the herniated L4-5 disc except that there was a slim membrane-like structure covering it. The patient was initially considered as type IIA LSNA skeptical according to Neidre and Macnad Classification. But detailed observation of the axial CT and MR sequences at L4-5 lateral recess space and sagittal CT and MR sequences at L5S1 intervertebral foramen found there was nerve-like structure, which was further confirmed to be the L5 nerve root by total unroofing of stenosed lateral recess. The membrane-like structure covering the L4-5 disc was confirmed to be the flattened right L5 nerve root compressed by herniated L4-5 disc and stenosed lateral recess, which emerged from the dura’s ventral-lateral side just above the L4-5 disc, the L5 nerve was stripped and pushed medially from its lateral boundary meticulously, L4-5 discectomy was done at right side. Intervertebral cages were inserted after L3-4 and L4-5 disc spaces preparation, following pedicle screw system fusion. Results: No nerve damage occurred intraoperatively. The patient was free of radiating pain to the left lower extremity the day after operation, two weeks later the radiating pain to the right lower extremity alleviated after temporary aggravating. Conclusion: type II lumbar nerve anomalies were not easily to be detected by CT or MR images preoperatively, that closer distance between the conjoined nerves existing the L4-5 foramen and careless observation was responsible for missed diagnosis preoperatively. That the flattened right L5 nerve covering the L4-5 disc was difficult to be recognized intraoperatively for losing its typical contour and color was responsible for misdiagnosing type-IIB anomaly as IIA LSNA.. The operators should be alert and observed carefully in case of misdiagnosing.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the complications of surgical treatments for femoral intertrochateric fractures using dynamic hip screw (DHS).</p><p><b>METHODS</b>From Jan. 2002 to Dec. 2007, sixty-nine patients with intertrochanteric fractures were treated by dynamic hip screw fixation included 27 males and 42 females,with an average age of 72.9 years ranging from 53 to 96 years. According to Evans classification there were 10 cases in type I ,21 in type II, 22 in type III, and 16 in type IV, of which 51 patients (73.9%) suffered from systematic diseases preoperatively.</p><p><b>RESULTS</b>Fifty-seven patients were followed up for 8 to 70 months (41 months on average). Four patients died, 17 cases occurrenced systematic complications postoperatively. Internal fixation related complications occurred in 12 patients. There were 8 cases with mechanical failure of DHS including 4 of screw loosen,3 of cutting-out of device through femoral head and neck and 1 of plate breakage. Five patients had a coxa vara, and delayed union occurred in 4 patients.</p><p><b>CONCLUSION</b>Unstable fracture pattern produced high percentage of mechanical failure. In such cases DHS should not be the first choice for treatment. The appropriate treatment should be in relation to pre-operative fracture stability and osteoporosis.</p>