Thoracic ossification of ligamentum flavum caused by skeletal fluorosis

Thoracic ossification of ligamentum flavum (OLF) caused by skeletal fluorosis is rare. Only six patients had been reported in the English literature. This study reports findings from the first clinical series of this disease. This was a retrospective study of patients with thoracic OLF due to skeletal fluorosis who underwent surgical management at the authors' hospital between 1993 and 2003. Diagnosis of skeletal fluorosis was made based on the epidemic history, clinical symptoms, radiographic findings, and urinalysis. En bloc laminectomy decompression of the involved thoracic levels was performed in all cases. Cervical open door decompression or lumbar laminectomy decompression was performed if relevant stenosis was present. Neurological status was evaluated preoperatively, at the third day postoperatively, and at the end point of follow-up using the Japanese Orthopaedic Association (JOA) scoring system of motor function of the lower extremities. A total of 23 cases were enrolled, 16 (69.6%) males and 7 (30.4%) females, age ranging from 42 to 72 years (mean 54.8 years). All patients came from a high-fluoride area, and 22 (95.7%) had dental fluorosis. Medical imaging showed OLF together with ossification of many ligaments and interosseous membranes, including interosseous membranes of the forearm (18/23 patients 78.3%), leg (14/23 patients 60.9%), and ribs (11/23 patients 47.8%). OLF was classified into five types based on MRI findings: localized (4/23 patients 17.4%), continued (12/23 patients 52.2%), skip (3/23 patients 13.0%), combining with anterior pressure (2/23 patients 8.7%), and combining with cervical and/or lumbar stenosis (2/23 patients, 8.7%). Urinalysis showed a markedly high urinary fluoride level in 14 of 23 patients (60.9%). Patients were followed up for an average duration of 4 years, 5 months. Paired t-test showed that the JOA score was slightly but nonsignificantly increased relative to preoperative measurement 3 days after surgery (P = 0.0829) and significantly increased at the end of follow-up (P = 0.0001). In conclusion, Fluorosis can cause ossification of thoracic ligamentum flavum, as well as other ligaments. Comparing with other OLF series, a larger number of spinal segments were involved. The diagnosis of skeletal fluorosis was made by the epidemic history, clinical symptom, imaging study findings, and urinalysis. En bloc laminectomy decompression was an effective method.     

Intraoperative somatosensory evoked potential monitoring during anterior cervical discectomy and fusion in nonmyelopathic patients--a review of 1,039 cases.

BACKGROUND CONTEXT: Intraoperative somatosensory evoked potential (SSEP) monitoring has been shown to reduce the incidence of new postoperative neurological deficits in scoliosis surgery. However, its usefulness during cervical spine surgery remains a subject of debate. PURPOSE: To determine the utility of intraoperative SSEP monitoring in a specific patient population (those with cervical radiculopathy in the absence of myelopathy) who underwent anterior cervical discectomy and fusion (ACDF) surgery. STUDY DESIGN: Retrospective review. PATIENT SAMPLE: A total of 1,039 nonmyelopathic patients who underwent single or multilevel ACDF surgery. The control group (462 patients) did not have intraoperative SSEP monitoring, whereas the monitored group (577 patients) had continuous intraoperative SSEP monitoring performed. OUTCOME MEASURE: A new postoperative neurological deficit. METHODS: SSEP tracings were reviewed for all 577 patients in the monitored group and all significant signal changes were noted. Medical records were reviewed for all 1,039 patients to determine if any new neurological deficits developed in the immediate postoperative period. RESULTS: None of the patients in the control group had any new postoperative neurological deficits. In the monitored group there were six instances of transient SSEP changes (1 due to suspected carotid artery compression; 5 thought to be due to transient hypotension) which resolved with the appropriate intraoperative intervention (repositioning of retractors; raising the arterial blood pressure). Upon waking up from anesthesia, one patient in the monitored group had a new neurological deficit (partial central cord syndrome) despite normal intraoperative SSEP signals. CONCLUSIONS: ACDF appears to be a safe surgical procedure with a low incidence of iatrogenic neurological injury. Transient SSEP signal changes, which improved with intraoperative interventions, were not associated with new postoperative neurological deficits. An intraoperative neurological deficit is possible despite normal SSEP signals.     

Use of small suture anchors in cervical laminoplasty to maintain canal expansion: a technical note

OBJECTIVE: Open door laminoplasty is a commonly performed procedure for the treatment of cervical spine pathology. One complication of this procedure is closure of the hinge and subsequent restenosis. A simple and effective method of using suture anchors to stabilize posterior elements has been previously described. The aim of this paper is to describe our experience using 2.0-mm suture anchors to maintain canal expansion. METHODS: Results of 42-consecutive patients who were treated with a modified cervical open-door laminoplasty were reviewed. The modification involves the use of original Hirabayashi technique, but augmenting the canal expansion with 2.0-mm suture anchors at C3, C5, and C7 levels. Additionally, nonabsorbable sutures are placed at C4 and C6 levels as described by Hirabayashi. The technical issues and short-term radiographic outcomes were evaluated. RESULTS: None of the 42 patients who had the door secured with 2.0-mm suture anchors had closure of the hinge. Additionally, the suture anchors maintained their position without loosening or "pull-outs" on postoperative follow-up radiographs. There were 3 short-term complications: 1 was a small dural-tear which was repaired intraoperatively without further sequelae, and the other 2 were both epidural hematomas that required emergent return to the operating room for evacuation. All 3 patients had an uneventful recovery without a new neurologic deficit. CONCLUSIONS: This paper reviews a simple and effective method for maintaining canal expansion in open-door laminoplasty. Because of its technical simplicity, 2.0-mm suture anchors may be a safer alternative than other devices currently popular for this purpose.     

Digital reconstruction and donor site resurfacing: a two-flap technique

Use of a great toe pulp flap is one of the methods to repair partial soft-tissue defect of the thumb or other digits. However, the conventional application of free skin grafts to close the donor site may bring donor-site morbidity. The authors present a two-flap technique that a reverse first dorsal metatarsal artery (FDMA) flap resurfaces the defect of the free great toe pulp flap. Six patients with soft-tissue defects of the thumbs or fingers were treated with this technique. Both the pulp and reverse flaps survived uneventfully after reconstruction of the thumbs and fingers. The reverse flap to resurface the donor site on the great toe was sensate and durable. Satisfactory appearance and function were gained in all patients. Results revealed that this technique can be accepted as an alternative method when treating soft tissue defect of the thumb or finger.     

Response of lumbar paraspinal muscles spindles is greater to spinal manipulative loading compared with slower loading under length control.

BACKGROUND CONTEXT: Spinal manipulation (SM) is a form of manual therapy used clinically to treat patients with low back and neck pain. The most common form of this maneuver is characterized as a high-velocity (duration <150 ms), low-amplitude (segmental translation <2 mm, rotation <4 degrees , and applied force 220-889 N) impulse thrust (high-velocity, low-amplitude spinal manipulation [HVLA-SM]). Clinical skill in applying an HVLA-SM lies in the practitioner's ability to control the duration and magnitude of the load (ie, the rate of loading), the direction in which the load is applied, and the contact point at which the load is applied. Control over its mechanical delivery is presumably related to its clinical effects. Biomechanical changes evoked by an HVLA-SM are thought to have physiological consequences caused, at least in part, by changes in sensory signaling from paraspinal tissues. PURPOSE: If activation of afferent pathways does contribute to the effects of an HVLA-SM, it seems reasonable to anticipate that neural discharge might increase or decrease in a nonlinear fashion as the thrust duration approaches a threshold value. We hypothesized that the relationship between the duration of an impulsive thrust to a vertebra and paraspinal muscle spindle discharge would be nonlinear with an inflection near the duration of an HVLA-SM delivered clinically (<150 ms). In addition, we anticipated that muscle spindle discharge would be more sensitive to larger amplitude thrusts. STUDY DESIGN/SETTING: A neurophysiological study of spinal manipulation using the lumbar spine of a feline model. METHODS: Impulse thrusts (duration: 12.5, 25, 50, 100, 200, and 400 ms; amplitude 1 or 2 mm posterior to anterior) were applied to the spinous process of the L6 vertebra of deeply anesthetized cats while recording single unit activity from dorsal root filaments of muscle spindle afferents innervating the lumbar paraspinal muscles. A feedback motor was used in displacement control mode to deliver the impulse thrusts. The motor's drive arm was securely attached to the L6 spinous process via a forceps. RESULTS: As thrust duration became shorter, the discharge of the lumbar paraspinal muscle spindles increased in a curvilinear fashion. A concave-up inflection occurred near the 100-ms duration eliciting both a higher frequency discharge compared with the longer durations and a substantially faster rate of change as thrust duration was shortened. This pattern was evident in paraspinal afferents with receptive fields both close and far from the midline. Paradoxically, spindle afferents were almost twice as sensitive to the 1-mm compared with the 2-mm amplitude thrust (6.2 vs. 3.3 spikes/s/mm/s). This latter finding may be related to the small versus large signal range properties of muscle spindles. CONCLUSIONS: The results indicate that the duration and amplitude of a spinal manipulation elicit a pattern of discharge from paraspinal muscle spindles different from slower mechanical inputs. Clinically, these parameters may be important determinants of an HVLA-SM's therapeutic benefit.     

A comparison of the effectiveness of mitomycin C and 5-fluorouracil in the prevention of peridural adhesion after laminectomy

OBJECT: The effectiveness of the topical application of mitomycin C (MMC) or 5-fluorouracil (5FU) in preventing peridural adhesion after laminectomy was compared in this study. METHODS: Laminectomies were performed at L-1 in 30 rats. Cotton pads soaked with 0.1 mg/ml MMC, 25 mg/ml 5FU, or 9 mg/ml saline (control) were applied to the operative sites. To evaluate neurological deficits pre- and postoperatively, somatosensory evoked potentials were monitored and the Basso-Beattie-Bresnahan locomotion test was performed. Four weeks postlaminectomy the rats were killed, and peridural scar adhesion was evaluated histologically. The level of hydroxyproline, the area of peridural scar tissue, and the number of fibroblasts were determined. The degree of peridural adhesion was classified according to the Rydell standard. RESULTS: No obvious adhesion formed in the rats in the MMC group, but severe peridural adhesions were found in those in the 5FU and control groups. The content of hydroxyproline, the area of peridural scar tissue, and the number of fibroblasts in the MMC group were significantly lower than those in the 5FU and control groups. CONCLUSIONS: The topical application of MMC rather than 5FU may be a successful method of preventing postlaminectomy peridural adhesions.     

Impaired hepatic regeneration by ischemic preconditioning in a rat model of small-for-size liver transplantation

OBJECTIVE: Graft size is one of the major risk factors in adult-to-adult living donor liver transplantation and rapid regeneration is an essential post-operative requirement. Ischemic preconditioning (IPC) has been shown to be an effective strategy in the reduction of hepatic ischemia-reperfusion injury and stimulation of liver regeneration. This study was designed to evaluate the effects of IPC on liver regeneration in small-for-size liver grafts. METHODS: We employed a rat orthotopic liver transplantation model using small-for-size (30%) grafts, in the presence or absence (control) of IPC (10 min of ischemia followed by 15 min of reperfusion). Survival rate, graft injury, hepatocellular proliferation, cell cycle progression, Stat3 activation, as well as TNF-alpha and IL-6 expression were assessed. RESULTS: IPC significantly enhanced the extent of graft injury and hindered hepatic regeneration in small-for-size liver grafts. The 7-day survival rate was also reduced by IPC, but failed to reach statistical significance. IPC did not affect TNF-alpha levels, but significantly decreased the elevation of IL-6 after reperfusion. These findings were correlated with down-regulation of cyclin E and cyclin D1, and decreased numbers of PCNA-positive nuclei in IPC grafts. These results were inconsistent with Stat3 activation, as P-Stat3 exhibited a stronger and prolonged pattern of expression in the IPC group, compared to controls. CONCLUSIONS: Ischemic preconditioning may impair liver regeneration in small-for-size liver grafts by decreasing IL-6 and blunting cell cycle progression, through a mechanism at least partially independent of Stat3.     

Delayed fracture of a ceramic insert with modern ceramic total hip replacement

We report a case of ceramic liner fracture in a 34-year-old man that occurred 1 year 9 months after total hip arthroplasty with a BiCONTACT (Aesculap, Tuttlingen, Germany) ceramic-on-ceramic prosthesis. The ceramic liner was found within the metal shell in 4 large pieces and multiple small fragments in the peripheral portions. Its condition indicated that the possible mechanism of late ceramic liner chip fracture was repeated episodes of impingement between the prosthetic neck and the edge of the ceramic liner. Squatting, kneeling, and sitting cross-legged caused impingement. These positions are more common in Asian populations than in Western populations. After the joint was thoroughly irrigated, a new modular ceramic liner and a 28-mm ceramic head were implanted.