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Biomedical subjects

Kingsley R Chin

Publications and source records attributed to Kingsley R Chin.

At least 19 recordsLinked to original sources
PubMed2006

Spinal cord compression in a patient with multiple hereditary exostoses caused by breast adenocarcinoma metastatic to osteochondromas of the spine: case report.

STUDY DESIGN: Case report. OBJECTIVE: To report on thoracic spinal cord compression caused by a mass in a 66-year-old female with new onset of myelopathic symptoms and a history of multiple hereditary exostoses. SUMMARY OF BACKGROUND DATA: To our knowledge, there have been no previous reports of spinal cord compression in a patient with multiple hereditary exostoses caused by breast adenocarcinoma metastatic to osteochondromas of the spine. METHODS.: Chart, pathologic, and radiographic documentation of the preoperative and postoperative clinical course of the patient was used. RESULTS: The patient had resolution of her neurologic symptoms following wide surgical excision, decompression, and stabilization from T2 to T10. The patient's mass was found to be breast adenocarcinoma metastatic to osteochondromas of the spine. CONCLUSIONS: When faced with a patient with a history of multiple hereditary exostoses with new onset of myelopathic symptoms and a mass compressing the spinal cord, the clinician's differential should be broad and always initially include a metastatic lesion, osteochondroma, or chondrosarcoma.

Adenocarcinoma↗
PubMed2006

Mastication causing segmental spinal motion in common cervical orthoses.

STUDY DESIGN: In vivo fluoroscopic quantification of segmental cervical spinal motion in asymptomatic volunteers during mastication. OBJECTIVE: To quantify the degree of segmental cervical spine motion in patients during mastication and while wearing several commonly used cervical orthoses. SUMMARY OF BACKGROUND DATA: Cervical orthoses are routinely used to stabilize the cervical spine after trauma or cervical fusion and are, in some cases, prescribed to be worn at all times, including during eating. METHODS: Seven volunteers with an average age of 31 years (range, 26-42 years) had 5 seconds of continuous lateral cervical fluoroscopic imaging while they chewed gum without any cervical orthosis (control) and while wearing a soft collar turned forward then backward, a Philadelphia collar, a Miami J collar, or a two-poster brace. Still images were created from the fluoroscopy video, which allowed for quantification of the amount of segmental motion. RESULTS: All cervical collars produced statistically greater motion at occiput-C1 and C1-C2 when compared with no collar. The motion was greatest at the occiput-C1 junction and decreased to the C4 level. No motion was detected in any subject in any brace below C4. The two-poster brace produced the most segmental motion at occiput-C1 (6.3 degrees +/- 2.0 degrees) compared with the soft collar turned backwards (1.9 degrees +/- 1.9 degrees). No subject had any segmental motion below C2 in the soft collar. No segmental spinal motion was observed without a cervical brace. CONCLUSIONS: To limit upper cervical spine segmental motion during mastication, for patients with unstable cervical spines, we propose a two-poster brace with removal of the mandibular component to allow for free mandibular action. For stable spines, we propose a soft collar turned backwards. Patients should be educated with this information.

Adult↗
PubMed2006

Changes in the iliac crest-lumbar relationship from standing to prone.

BACKGROUND CONTEXT: It is known that positioning patients on the Jackson and Andrews operative tables causes changes in lumbar lordosis and pelvic rotation. However, it is unknown if the relationship between the iliac crest and underlying lumbar levels, in particular the L4-L5 interspace, changes from standing to prone on these tables. PURPOSE: To assess the changes in the relationship between the iliac crests and lumbar spinal levels from standing to prone on two different operative positions using the Jackson and Andrews frames. STUDY DESIGN/SETTING: Comparative analysis of iliac crest position relative to spinal levels in the preoperative standing position and while positioned on the Jackson and Andrews frames. PATIENT SAMPLE: 48 randomly selected patients who underwent spinal surgery on either the Jackson or Andrews frame. OUTCOME MEASURES: Imaging. METHOD: Comparative measurements were made of the preoperative and intraoperative plain lateral lumbar radiographs. The location of the superior border of the iliac crest relative to the L4 lumbar spine level was compared between radiographs. RESULTS: Preoperatively, the iliac crest aligned with L4/L4-L5 spinal level in 79.2% of the 48 patients compared with 85.5% of intraoperative cases (p=.59). Intraoperative iliac crest level aligned with the L4/L4-L5 level in 80.8% and 90.9% of the patients on the Andrews and Jackson tables respectively (p=.43). Thirty-four patients (70.8%) demonstrated no change in iliac crest alignment between intraoperative and preoperative radiographs. There was a trend for the iliac crest to shift cephalad with operative positioning. CONCLUSION: Approximately 30% of patients demonstrated changes in the relationship between the iliac crest and lumbar levels between standing and positioning prone. The intraoperative position of the iliac crest aligned more accurately with the L4/L4-L5 spine level on the Jackson and Andrews frame compared with preoperative standing radiographs respectively. Further biomechanical studies should investigate the implication for lumbopelvic fixation.

Adult↗
PubMed2006

Postembolization paralysis in a man with a thoracolumbar giant cell tumor.

Giant cell tumors are hypervascular tumors that represent approximately 5% of all primary bone neoplasms. Vertebral tumors often require surgery to maintain spinal stability or to relieve spinal cord and nerve root compression. However, surgical resection of hypervascular tumors like giant cell tumors can be hazardous because of the risk of excessive intraoperative hemorrhage. Preoperative embolization can be useful to decrease perioperative blood loss in primary and metastatic vertebral tumors, and preoperative embolization for vertebral tumor surgery is relatively safe. We report a patient who had the unusual but serious complications of paralysis and paresthesia at the T12 vertebra and below as a result of preoperative embolization. At 6 months followup, the patient was disease-free but without neurologic function from T12 and below. Therefore, it is imperative physicians be aware of the possible preoperative embolization complication of cord infarction and the safety measures proposed in this article to avoid this complication.

Blood Loss, Surgical↗
PubMed2006

Use of spinous processes to determine drill trajectory during placement of lateral mass screws: a cadaveric analysis.

OBJECTIVE: Prior cadaveric research showed that the lateral mass and facets are landmarks to determine the initial starting point for lateral mass screws and that the optimum screw trajectory was 30 degrees lateral and 15 degrees cephalad. The missing link was an intraoperative landmark to guide the trajectory for drilling according to these angles. The authors hypothesized that spinous processes can be used to guide the trajectory for lateral mass screw placement. METHODS: The authors analyzed 144 lateral masses of 72 cervical vertebrae in 18 cadavers (7 males and 11 females). The lateral and cephalocaudad angles were measured for each lateral mass from C3 to C6 while using the spinous processes of the adjacent three caudad vertebrae at each level to guide the starting trajectories for a total of 864 angles. The lateral and cephalad trajectory angles at each spinous process relative to the starting hole were compared with 30 degrees and 15 degrees . For each angle measured at a particular level, the same starting hole was used in the lateral mass, and the superolateral cortex of each spinous process was the most medial point. RESULTS: When drilling for the C3 and C4 lateral mass screws, the C4 and C5 spinous processes provided an accurate starting point, respectively, for the lateral angle but moderately overestimated the cephalocaudad angle. For C5 and C6 lateral mass screws, the C6 and C7 spinous processes provided an accurate starting point, respectively, for both the lateral and the cephalocaudad angles. CONCLUSION: The spinous processes can be an accurate local anatomic guide for lateral mass screw trajectory and will allow greater safety while drilling before performing laminectomies. These guides may change in patients with cervical spinal deformities.

Bone Screws↗
PubMed2006

Prospective evaluation of a 3-blade speculum cannula for minimally invasive lumbar microdiscectomy.

Minimally invasive spine technology is still in an evolutionary stage. This prospective study reports the technical feasibility, benefits, and limitations of using a 3-blade speculum cannula for minimally invasive lumbar microdiscectomies. We studied 52 consecutive patients, 24 males and 28 females, with a mean age of 36.1 years (range 20 to 68 years) and body mass index of 29.6 who underwent a microdiscectomy using this access device that opened to create a cylindrical working channel. We prospectively documented the length of the incision, estimated blood loss, length of surgery, outcomes using the visual analog scale for leg pain, and complications. The average incision length was 20.9 mm (range 13 to 30 mm). Average blood loss was less than 50 mL. Ninty-six percent of the patients had complete resolution of their radicular leg pain with improved mean visual analog scale scores from 8 to 0.3 postoperatively (P<0.5). Mean surgical time decreased with experience from 135 minutes for the first 15 patients, 103 minutes for the next 22, and 75.2 minutes for the last 15, to an overall mean of 108 minutes (range 51 to 188 minutes) and a 56% decrease for the last 38 patients. Body mass index did not affect surgical time or incision length. Seventy-five percent of the patients were discharged on the day of surgery and the remainder within 23 hours. Two symptomatic hematomas required reoperation using the retractor at 3 days and 4 weeks postoperatively. This new speculum minimal access device was effective for lumbar microdiscectomy in limiting the size of the incision without the need for sequential dilation, providing excellent visualization with the aid of a microscope, allowing same-day discharge after surgery, and demonstrating improved outcomes even in obese patients. This device may provide insights for the improvement of design considerations for other minimally invasive access devices.

Adult↗
PubMed2006

Sacral fractures.

Sacral fractures most commonly occur after pelvic ring injuries but occasionally in isolation. Although the true incidence of sacral fractures is unknown, an estimated 30% are identified late. Sequelae of inappropriately treated or untreated sacral fractures include persistent pain, decreased mobility, and neurologic compromise. Because these fractures often result from high-energy trauma, concomitant injuries should be suspected. A thorough physical examination, including a detailed neurologic assessment and radiographic evaluation, is necessary to determine treatment. Computed tomography of the pelvis/sacrum can provide significant information about fracture pattern. Surgical intervention, often as a combination of neural decompression and stabilization, is indicated in patients with neurologic deficits, significant soft-tissue compromise, and lumbosacral instability. Patient satisfaction with surgical intervention has not been definitively documented, although neurologic improvement with timely intervention has been noted.

Fracture Fixation↗
PubMed2005

Infrapatellar fat pad disruption: a radiographic sign of patellar tendon rupture.

UNLABELLED: After knee trauma, radiographs showing patella alta supercede other signs that suggest patellar tendon rupture. However, without patella alta the diagnosis may be missed. A standard lateral radiograph with the knee flexed showed the infrapatellar fat pad as a dark band with a smooth contour. Our pilot study identified a disruption of the fat pad contour as a radiographic sign of tendon rupture. Two blinded reviewers independently analyzed randomly selected lateral radiographs of the knees of 14 patients with knee injuries. Seven patients had confirmed ruptures diagnosed at surgery, and the other patients had different diagnoses. There were 12 men and two women with an average age of 49 years (range, 20-81 years). One observer detected five of the seven disrupted tendons and six of the seven intact tendons. The other observer detected six of the seven disrupted tendons and all seven intact tendons. Disruption in the contour of the infrapatellar fat pad on routine lateral view radiographs was a reasonably reliable sign of patellar tendon rupture. Diagnostic accuracy should increase when used with the patient's history, physical examination, and other radiographic signs. Absence of this sign should not supersede other suggestive signs of patella tendon rupture. LEVEL OF EVIDENCE: Diagnostic study, Level II (development of diagnostic criteria on consecutive patients--with universally applied reference "gold" standard). See the Guidelines for Authors for a complete description of levels of evidence.

Adipose Tissue↗
PubMed2005

Patient behavior if given their surgeon's cellular telephone number.

Technologic advances in communications potentially may affect the patient-doctor relationship. We assessed call patterns, reasons for calling, and attitudes if patients had their surgeon's cellular telephone number, to determine if there are potential benefits to this practice. Postoperative calls made by patients to the surgeon, secretary, and surgical scheduler were categorized as urgent or nonurgent. Twenty of 32 (63%) consecutive patients made 65 calls during a 2-month period. Only 12 calls (18%) were to the surgeon. Fifty percent were urgent, as opposed to 14% and 15% of calls to the secretary and surgical scheduler, respectively. Subsequently, 201 patients were prospectively administered a 10-question survey assessing patient attitudes if given direct access to their surgeon. Eighty percent owned a cellular telephone, 85% would call the surgeon, and 30% would prefer the surgeon as the first line of communication. Communicating through E-mail or home phone was less desirable than through the nurse or cellular telephone. Seventy-two percent thought that having cellular telephone access suggested that their surgeon was more caring. Patients desired to communicate directly with surgeons, but act with restraint and call as a last resort for mostly urgent issues if given the physician's cellular telephone number. The cellular telephone has promising benefits for the patient-physician relationship.

Adult↗
PubMed2005

Transforaminal cervical blood patch for the treatment of post-dural puncture headache.

A 40-yr-old woman received a series of three interlaminar epidural steroid injections for the treatment of axial neck pain secondary to degenerative disc disease. Immediately after her third injection, she experienced symptoms of a dural puncture-induced headache. This headache persisted on a daily basis for 3 mos, despite two epidural blood patches using an interlaminar approach, which was finally completely abated with a transforaminal blood patch. The headache was immediately relieved and remained alleviated through the follow-up interval of 1 yr. In this patient, a fluoroscopically guided transforaminal epidural blood patch proved to be more effective than the classic blind interlaminar approach in the treatment of post-dural puncture headache.

Adult↗
PubMed2005

Traumatic atlanto-occipital dislocation in children.

BACKGROUND: Traumatic atlanto-occipital dislocation in children and adolescents is a rare and often fatal injury. Although historically most reported cases have been fatal, the advent of modern prehospital care has led to an increase in survival following this injury. As a consequence, some patients may achieve or maintain satisfactory neurologic function following early intervention, stabilization, and definitive management. We analyzed the data on children and adolescents in whom traumatic atlanto-occipital dislocation had been treated with modern resuscitation techniques at our institution. METHODS: Atlanto-occipital dislocation is defined as disruption of the ligaments and other supporting soft tissues as indicated by displacement in either a transverse or vertical direction. With use of the Trauma Registry database at our institution, we identified sixteen such injuries that had occurred between 1986 and 2003. The hospital charts, clinic notes, and radiographs were reviewed. A careful neurological evaluation was performed for all of the survivors at the time of the latest follow-up. RESULTS: The mean age of the sixteen patients at the time of the injury was 7.6 years. The mechanisms of injury were diverse. The mean Glasgow Coma Scale score was 7.4 points. Eleven of the sixteen patients underwent intubation in the field, two were intubated in the emergency department, and three were not intubated. Eight of the sixteen patients were declared dead on arrival in the emergency department. The eight surviving patients initially were immobilized with either a halo vest or another orthosis. All patients except one received intravenous steroids in the emergency department. Three of the patients who survived the initial injury subsequently died while undergoing neurosurgical procedures for the treatment of extensive intracranial injuries. Four of the remaining five survivors underwent occiput-C2 fusion, and one was managed with a Minerva cast. At the time of the final follow-up, at a mean of 4.2 years after the injury, one patient was neurologically normal, three had mild spastic hemiparesis and were very functional, and one had spastic quadriplegia and was ventilator-dependent. CONCLUSIONS: Prompt recognition and treatment of traumatic atlanto-occipital dislocation in children and adolescents can result in improved survival. Early diagnosis, prompt intubation, early and adequate immobilization of the head and neck, and the use of intravenous steroids appear to facilitate survival. We recommend arthrodesis from the occiput to C2 (or the nearest adjacent intact and stable vertebra caudad to C2) for all children who survive a traumatic atlanto-occipital dislocation, particularly those with an incomplete spinal cord injury.

Adolescent↗
PubMed2004

Revision surgery for patellar dislocation after primary total knee arthroplasty.

This study evaluated risk factors for patellar dislocation after primary total knee arthroplasty and determined functional outcomes in patients following revision. Thirty-nine knees in 39 patients averaging 68 years (range, 27-91 years) at the time of revision were evaluated at a mean of 3.2 years (range, 2-7 years). Mean Knee Society and Function scores significantly improved from 34 and 35 to 77 and 54, respectively. Patellar dislocation most commonly resulted from errors in technique such as soft-tissue imbalance and malaligned components that led to poor tracking of the patella. Patellar tracking only improved after soft-tissue realignment in combination with revision of malaligned or loose components. Although revision significantly improved active knee extension and Knee Scores, two thirds of the patients had residual disabilities and pain.

Adult↗
PubMed2003

Salvage of distal tibia metaphyseal nonunions with the 90 degrees cannulated blade plate.

Nonunion of distal tibia metaphyseal fractures after trauma is a major problem. Treating these nonunions is made more challenging by the presence of symptomatic ipsilateral tibiotalar arthrosis. The current study examined the use of the 90 degrees cannulated blade plate as an alternative method of stable internal fixation for 13 distal tibia metaphyseal nonunions and simultaneous fusion of three arthritic tibiotalar joints in 13 patients (seven males and six females) with an average age of 42.4 years (range, 21-73 years). Each patient had an average of three prior procedures (range, 2-6). Patients were followed up for an average of 34.2 months (range, 24-55 months). All 13 patients achieved radiographic and clinical union an average of 15.6 weeks (range, 12-20 weeks) from the date of the definitive procedure. There were two broken screws, but no secondary procedures were required to obtain fusion. All patients were ambulatory without support at the last followup. The implant proved effective for stable internal fixation of distal tibia metaphyseal nonunions alone or with simultaneous fusion of the tibiotalar joint.

Adult↗
PubMed2002

Nonunion of nonoperatively treated fractures of the radial head.

Although fractures of the radial head traditionally are not associated with healing problems, delayed union and nonunion are being seen more frequently after operative and nonoperative treatment. Given the tenuous blood supply to the head of the radius, problems with healing are not surprising. As the current review of five patients with nonunion of nonoperatively treated radial head fractures treated during a 6-year period shows, healing problems rarely are symptomatic and often may go unrecognized. Even when the fracture still is apparent on radiographs obtained more than 1 year after the injury, healing still may occur. Operative treatment, although rarely necessary, achieved union in one of the current patients.

Adult↗
PubMed2002

Treatment of advanced primary and recurrent diffuse pigmented villonodular synovitis of the knee.

BACKGROUND: Diffuse pigmented villonodular synovitis of the knee is a difficult tumor to eradicate. We report our experience with a combined open posterior and anterior synovectomy with and without adjuvant postoperative radiation therapy in patients with advanced extracapsular disease. METHODS: A single surgeon operated on forty patients, with an average age of thirty-five years (range, fourteen to sixty-eight years), who had diffuse pigmented villonodular synovitis of the knee. All patients had been referred to us after having initially undergone arthroscopic or open surgical procedures without eradication of the disease. Patients were retrospectively placed into one of three groups: Group I received surgery alone (five patients), Group II had surgery and intra-articular radiation synovectomy with use of dysprosium-165 (thirty patients), and Group III had surgery and external beam radiation (five patients). Adjuvant radiation was performed three months postoperatively. Magnetic resonance imaging was used for all patients for preoperative staging and postoperative follow-up. RESULTS: The average Knee Society score for the entire series improved from 61 points preoperatively to 92 points at the time of follow-up, at an average of five years (range, 1.5 to eight years) (p < 0.001). There was also a significant (p < 0.001) increase in the average range of motion of the knees across all groups. On the basis of the Knee Society scores, thirty-seven patients (93%) had a good or excellent result, two patients had a fair result, and one patient had a poor result. Complications included stiffness requiring manipulation in three knees, one case of reflex sympathetic dystrophy, advanced osteoarthritis leading to a total knee replacement in four patients, and seven recurrences (a prevalence of 18%) after operative treatment and radiation therapy. CONCLUSIONS: This surgical technique allows excellent visualization and removal of intra-articular and extra-articular diffuse pigmented villonodular tissue and yields excellent functional results and a low prevalence of knee stiffness. However, the rate of recurrence detected by magnetic resonance imaging was 18%. Adjuvant intra-articular radiation therapy may be beneficial for eradication of small foci of residual disease, but complete resection of all pigmented villonodular tissue appears to be the key to preventing recurrence. Magnetic resonance imaging was essential for accurate preoperative staging of the tumor and for follow-up since the presence of residual disease did not reliably correlate with the clinical findings. Patients with minimal degenerative arthritis and primary or recurrent extra-articular disease will benefit most from this approach.

Adolescent↗
PubMed2002

Intraoperative measurements of male and female distal femurs during primary total knee arthroplasty.

The anteroposterior (AP) and medial-lateral (ML) dimensions of 200 consecutive osteoarthritic knees (100 males and 100 females) undergoing unilateral primary total knee arthroplasty were compared. For all patients, the mean AP dimension was 57.3 mm (range: 49-66 mm) and the dimension was 10.5% taller in height in men than women. The mean ML dimension was 71.6 mm (range: 56-85 mm), and the dimension was 13.7% wider in men than women. The mean AP/ML ratio was 0.8 for all patients, 0.82 (range: 0.73-0.93) for females and 0.79 (range: 0.70-0.89) for males (P<.001). The data suggest that for any given AP femoral dimension, women tend to have a narrower ML dimension than men, independent of AP height, and an AP/ML ratio of 0.80 most closely approximates a standard-sized distal femur across gender. This report documents important gender differences that may serve as a reference for femoral implant designers and knee surgeons.

Adult↗