Biomedical subjects

J Klekamp

Publications and source records attributed to J Klekamp.

At least 19 recordsLinked to original sources

PubMed2002

The pathophysiology of syringomyelia - historical overview and current concept.

Various ideas and hypotheses have been brought forward to explain the development of syringomyelia in the past two centuries. None of them offers a sufficient basis to serve as a concept for the treatment of all affected patients. Apart from a discussion of the different hypotheses this paper proposes a new pathophysiological concept based on clinical, experimental and literature studies. Syringomyelia is understood as a state of chronic interstitial edema of the spinal cord due to accumulation of extracellular fluid (ECF). This accumulation is caused by a cascade of events starting with obstruction of cerebrospinal fluid (CSF) flow and/or spinal cord tethering which ultimately alter ECF flow and increase ECF volume. Treatment should be targeted against the pathological process which causes CSF flow obstruction and cord tethering to inhibit this pathophysiological process at a decisive point.

Animals↗

PubMed2001

Thoracic intradural extramedullary lipomas. Report of three cases and review of the literature.

BACKGROUND: Indication for surgery and the surgical strategy for treatment of spinal intradural lipomas are still discussed controversially. Among spinal lipomas the cervicothoracic region is rarely affected. We report on our experience with spinal decompression for the treatment of three intradural thoracic lipomas. FINDINGS: Three adult patients with extramedullary intradural lipomas of the thoracic spinal cord demonstrated progressive neurological symptoms and signs without evidence of growth of the lipoma. All patients underwent surgery with decompression of the affected spinal levels. No attempt was made to reduce the size of the lipomas. Postoperatively, each patient demonstrated significant clinical improvement. Interpretation. Attempts to remove lipomas are associated with significant risks of surgical morbidity. Lipomas are hamartomas which change their size according to alterations of body fat. Therefore, decompression of the affected spinal levels is sufficient to achieve significant neurological improvement.

Adult↗

PubMed2001

Disturbances of cerebrospinal fluid flow attributable to arachnoid scarring cause interstitial edema of the cat spinal cord.

OBJECTIVE: Spinal arachnoid scarring may be caused by trauma, inflammation, surgery, spinal instability, degenerative diseases, or malformations and may lead to progressive neurological deficits and syringomyelia. We wanted to investigate the effects of focal arachnoid scarring in the cervical spinal canal of cats on pressures in the subarachnoid space and spinal cord tissue, as well as on spinal cord histological features. METHODS: Twenty-nine adult cats were used for this study. Nine animals served as control animals, whereas 20 animals received a focal arachnoid scar at C1-C2, which was produced by placement of a kaolin-soaked fibrin sponge on the posterior surface of the spinal cord. After 4 months, pressure recordings above and below the scar, in the subarachnoid space and spinal cord, were performed. Elasticity measurements were performed with small bolus injections. Morphometric analyses of brain and ventricle volumes, sizes of the central canal, and sizes of the perivascular spaces in gray and white matter were also performed. RESULTS: No animal developed clinical or neurophysiological evidence of neurological symptoms at any time. In the kaolin-treated group, pressure recordings revealed a significant increase in the subarachnoid pressure at C1, because of the cerebrospinal fluid flow obstruction. Pressure gradients tended to increase at all measuring points. A significant difference was detected between the spinal cord and subarachnoid space at C2, where the intramedullary pressure exceeded the subarachnoid pressure. Elasticity was significantly increased in the spinal cord at C2. Intracranially, no evidence of hydrocephalus was observed. In the spinal cord, perivascular spaces were significantly enlarged in the posterior white matter above the arachnoid scar and in the central gray matter below the area of scarring in the cervical cord. CONCLUSION: Arachnoid scarring at C1-C2 produces an interstitial type of edema in the central gray matter below the area of scarring in the cat cervical cord, because of altered cerebrospinal fluid and extracellular fluid flow dynamics. These changes may be interpreted as the initial stage in the development of syringomyelic cavities.

Animals↗

PubMed2001

Spontaneous resolution of Chiari I malformation and syringomyelia: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: Indications for surgery and the surgical technique of foramen magnum decompression for patients with Chiari I malformation and syringomyelia are controversial issues. This case report supports the view that observation may be adequate for patients without progressive symptoms or with mild clinical symptoms. CLINICAL PRESENTATION: A 37-year-old woman presented with a 3-month history of burning dysesthesias and hypesthesia in her right arm. A neurological examination revealed hypesthesia in the right trigeminal distribution. A magnetic resonance imaging scan revealed a Chiari I malformation with syringomyelia between C2 and T2. No hydrocephalus was observed. CLINICAL COURSE: Because the patient's symptoms regressed spontaneously, surgery was not performed. Thirty-two months after her initial examination, the patient was asymptomatic. A second magnetic resonance imaging scan was obtained, which demonstrated complete spontaneous resolution of the Chiari I malformation and syringomyelia. CONCLUSION: We attribute the regression of the patient's symptoms to spontaneous recanalization of cerebrospinal fluid pathways at the foramen magnum, which most likely was due to rupture of the arachnoid membranes that had obstructed cerebrospinal fluid flow.

Adult↗

PubMed2001

Neurenteric cyst of the craniocervical junction. Report of three cases.

Neurenteric cysts of the craniocervical junction (CCJ) are very rare lesions. Their origin is the subject of long-standing controversy, but a failure during the embryogenic phase may be responsible for their formation. Accurate histopathological diagnosis may be difficult due to the similarity they share with other cystic lesions such as colloidal cysts, Rathke cysts, and cystic teratomas. Surgical removal is the treatment of choice for intracranial neurenteric cysts, but in some cases, infiltration of the surrounding structures may hinder complete resection. Three cases of neurenteric cysts located at the CCJ are reported.

Adult↗

PubMed1999

Prerequisites for fetal neurosurgery: management of central nervous system anomalies toward the 21st century.

With the dramatic technical advances in neuroimaging, it has become possible to diagnose central nervous system (CNS) anomalies in the fetus in utero with more precise morphological analysis. A new technique, high-resolution magnetic resonance (MR) imaging using heavily T2-weighted fast spin echo sequences, has been reported to solve motion artifact of the fetus. However, it has also been recognized that the morphological fetal CNS findings detected in early development are not always the final features: occasionally they may not be determined in diagnosis and may change developmentally or chronologically during the fetal life in utero. Certain factors of the fetal chronology of CNS anomalies can cause irreversible changes during fetal life. These include: (1) significant delay in the neuronal maturation process in fetal hydrocephalus developed in clinicoembryological stage II in the Perspective Classification of Congenital Hydrocephalus (PCCH), (2) secondary neural injury in the intactly developing spinal cord above the neural placode in fetus with spina bifida aperta (myeloschisis), (3) histological "evolution" of tumors or dysgenetic CNS, and (4) deformity of the normally developed intracranial or intraspinal CNS structures. Considering the current status of fetal surgery in general and technical advances promising improved outcomes, fetal neurosurgery can also be applied in the above-mentioned progressive pathology or pathophysiology in the fetal CNS. However, since the failure of the first trial of fetal neurosurgery in the 1980s, the prerequisites have still not been clarified. In order to use advanced neurosurgery techniques in the management of fetal CNS anomalies, these prerequisites have to be established.

Journal Article↗

PubMed1999

Surgical results for spinal meningiomas.

Among a series of 782 spinal tumors, 130 spinal meningiomas in 117 patients were operated in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany, between 1977 and 1998. Patients were followed postoperatively for up to 13 years (mean 20 +/- 33 months). Comparing the period of 1977 through 1987, before magnetic resonance imaging (MRI) was available, to the period of 1988 to 1998 revealed that the average history until diagnosis shortened by about 6 months during the second decade of this study (24 +/- 33 to 18 +/- 29 months; not significant). Consequently, the preoperative Karnofsky Score increased significantly (59 +/- 15 and 66 +/- 16; p < 0.05). The rates of complete resection and the postoperative neurological outcome, however, remained unchanged. Even though the overall prognosis of neurological deficits is favorable after complete resection of a meningioma, a subset of 18 patients had either en plaque growing or recurrent tumors that were more likely to be removed incompletely and to cause postoperative neurological problems, with a significantly worse Karnofsky Score after 1 year (57 +/- 12 and 77 +/- 12, respectively; p < 0.01) and a significantly higher recurrence rate after 5 years (86.7% and 20.4%, respectively; log rank test p = 0.0014). In conclusion, a favorable postoperative neurological outcome requires complete resection of the spinal meningioma. The advent of MRI has shortened the time until diagnosis and made it possible to perform surgery before severe deficits have occurred, but did not have a major impact on postoperative results. En plaque and recurrent meningiomas remain surgical challenges, as infiltration of surrounding structures and associated arachnoid scarring may render complete resection difficult to achieve.

Adolescent↗

PubMed1999

The use of vancomycin and tobramycin in acrylic bone cement: biomechanical effects and elution kinetics for use in joint arthroplasty.

We examined the effects of vancomycin on the compressive strength and fatigue life of bone cement and the pharmacokinetics and antimicrobial activity against methicillin-resistant Staphylococcus aureus of vancomycin eluted from bone cement, both alone and in combination with tobramycin. Two cements, Palacos and Simplex, were tested. Three antibiotic preparations were tested: lyophilized vancomycin (vancomycin-L), vancomycin powder (vancomycin-P), and tobramycin powder (Lilly, Indianapolis, IN). Although antibiotics did not significantly affect compressive strength, the fatigue life of bone cement was significantly decreased with vancomycin. Thus, fatigue testing revealed effects on cement strength not apparent by compression testing. Vancomycin-P had a substantially less detrimental effect on fatigue strength than vancomycin-L. Vancomycin-P elutes less efficiently than tobramycin. Although relatively little vancomycin-P eluted from bone cement, it retained biologic activity.

Anti-Bacterial Agents↗

PubMed1999

Extradural infections of the spine.

OBJECTIVES: We have observed a recent increase in the incidence of spinal extradural infections. To determine postoperative outcome and prognosis we have undertaken a retrospective study on patients with spinal extradural abscesses between 1978 and 1996 treated in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany. METHODS: Case records, outpatient files, operation notes, neuroradiological examinations and pathological reports were analysed. Neurological function was documented using a score system for each symptom. RESULTS: Twenty-two patients underwent 24 operations during the study period. Staphylococcus aureus was the organism most commonly isolated. Patients presented after a mean history of 1.8+/-2.6 months with acute development of severe para- or tetraparesis and were followed up for an average period of 6+/-7 months. Two groups were distinguished. One group was characterized by epidural collections of pus (14 patients). Two patients in this group were not operated due to their moribund state and died from uncontrollable septicemia. Two of the remaining 12 operated patients died within 30 days after surgery due to generalized septicemia or other medical problems unrelated to the spinal involvement. Of the ten surviving patients, five sustained major neurological deficits, whereas the remaining five patients made an incomplete recovery. The second group consisted of eight patients in a significantly better pre-operative health condition in whom granulomatous material was obtained during the operation and the outcome was considerably better. No patient in this group died. Six patients recovered with no or mild neurological deficits. CONCLUSION: Spinal extradural infections require immediate surgical intervention. Neurological outcome depends on the pre-operative neurological status. Survival is determined by the general health condition of the patient.

Abscess↗

PubMed1999

Risk factors associated with methicillin-resistant staphylococcal wound infection after spinal surgery.

We used the data from a retrospective case controlled study to identify risk factors for methicillin-resistant staphylococcal wound infection after spinal surgery. Thirty-five cases and 35 uninfected control patients were matched for indication for initial surgery and approximate operative date. Preoperative, intraoperative, and postoperative risk factors were examined. At our institution between 1989 and 1995, 35 adult patients developed spinal wound infection requiring operative debridement; 16 infections were caused by methicillin-resistant staphylococci (MRS). Significant risk factors for MRS infection were lymphopenia, history of chronic infections, alcohol abuse, recent hospitalization, and prolonged postoperative wound drainage. Patients with MRS infections were also somewhat less likely to have received vancomycin prophylaxis. In contrast, the only factor associated with infection caused by other pathogens was alcohol abuse. A number of preoperative risk factors were significantly associated with subsequent MRS spinal wound infection. Chemoprophylaxis with vancomycin should be targeted to patients at increased risk, because overuse may promote the emergence of vancomycin-resistant pathogens.

Adult↗

PubMed1998

Surgical results for spinal metastases.

Among a series of 740 spinal tumours treated in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany, between September 1977 and December 1996, 106 spinal metastases in 101 patients were operated on. After an average period of 4.0 +/- 6 months (2 days to 5 years) patients presented at an average age of 62 +/- 12 years. 79% of the tumours were operated on by a posterolateral approach, 12% by an anterior and the remaining 9% by an anterior and posterior approach. A complete resection was achieved for 43.4% of the metastases while 48.1% were removed partially, 7.5% were biopsied and one patient received an opiate pump. Operations were followed by radiotherapy, chemotherapy or hormone treatment. The overall local recurrence rates as determined by the Kaplan Meier method were 57.9% after 6 months, 69.3% after 1 year and 96% after 4 years. Multiple regression analyses revealed that an independent preoperative status of ambulation, favourable tumour histology, cervical level, complete resection, low number of affected vertebral bodies, and elective surgery were significant, independent predictors of a low rate of local metastatic recurrence. Postoperative neurological outcome was related to preoperative neurological deficits. 96% of patients walking preoperatively kept this ability for at least 3 months postoperatively. However, only 22% of patients unable to walk regained walking capacity for 3 months. Correspondingly, 89% of patients remained continent of urine postoperatively for 3 months while only 31% regained sphincter control for this amount of time postoperatively. In terms of postoperative survival, multiple regression analyses showed longer survival times for patients with a favourable tumour histology, independent ambulation, long history, male sex, cervical level, complete resection, posterior approach, no additional metastases in other organs, and no instability. The overall survival rates were 58.8% after 6 months, 48% after 1 year and 19.5% after 5 years postoperatively. In conclusion, surgery has a place in the treatment of patients with metastatic disease of the spine and neurological symptoms and/or spinal instability. The surgical strategy should be tailored according to the general health of the patient and expected time of survival. Primary radiotherapy should be administered to patients without neurological deficits or instability and to patients who cannot undergo or do not accept surgery.

Analgesia, Epidural↗

PubMed1998

Surgery of spinal nerve sheath tumors with special reference to neurofibromatosis.

OBJECTIVE: We conducted a retrospective study of 87 patients with spinal nerve sheath tumors to determine the overall clinical outcome and specific features in 20 patients affected with neurofibromatosis Types 1 and 2 (NF-1 and NF-2, respectively). METHODS: Case records, operation notes, outpatient files, and radiological examinations were analyzed for all patients treated between September 1977 and August 1994. Additional follow-up data were obtained using outpatient examinations, questionnaires, and telephone calls. RESULTS: During the study period, 128 spinal neuromas (i.e., schwannomas) and 6 neurofibromas in 87 patients were treated. Fifty-seven neuromas were associated with NF-2 in 17 patients and six neurofibromas with NF-1 in 3 patients. Patients with NF-2 and symptomatic neuromas presented with more severe neurological deficits compared to patients without NF-2. Eighty-six percent of the neuromas were removed completely. On average, most preoperative deficits or symptoms improved in patients without NF-2, whereas neurological symptoms remained unchanged in patients with NF-2. Multiple regression analysis revealed that partial removal, surgery of a recurrent tumor, NF-2, and old age predisposed for tumor recurrence. No increased risk of recurrence was observed for patients with NF-1. For patients without NF-2, we observed overall recurrence rates of 10.7% after 5 years and 28.2% after 10 and 15 years, respectively, as determined by Kaplan-Meier analysis. For NF-2, the recurrence rate at 5 years was 39.2%, and all tumors had recurred by 9 years. CONCLUSION: Spinal nerve sheath tumors carry an excellent prognosis in patients with NF-1 and in patients without neurofibromatosis. Symptomatic neuromas occurring in association with NF-2 present with more severe neurological deficits, demonstrate little postoperative improvement, and have a very high recurrence rate.

Adolescent↗

PubMed1998

A critical appraisal of syrinx cavity shunting procedures.

OBJECT: This study was conducted to evaluate the results of shunting procedures for syringomyelia. METHODS: In a follow-up analysis of 42 patients in whom shunts were placed in syringomyelic cavities, the authors have demonstrated that 21 (50%) developed recurrent cyst expansion indicative of shunt failure. Problems were encountered in patients with syringomyelia resulting from hindbrain herniation, spinal trauma, or inflammatory processes. A low-pressure cerebrospinal fluid state occurred in two of 18 patients; infection was also rare (one of 18 patients), but both are potentially devastating complications of shunt procedures. Shunt obstruction, the most common problem, was encountered in 18 patients; spinal cord tethering, seen in three cases, may account for situations in which the patient gradually deteriorated neurologically, despite a functioning shunt. CONCLUSIONS: Placement of all types of shunts (subarachnoid, syringoperitoneal, and syringopleural) may be followed by significant morbidity requiring one or more additional surgical procedures.

Cerebrospinal Fluid Pressure↗

PubMed1998

Results of elective lumbar discectomy for patients involved in the workers' compensation system.

We compared the outcomes from lumbar discectomy for patients who were workers' compensation claimants and/or who were involved in active litigation with patients who underwent elective lumbar discectomy, but who were not involved with either compensation or litigation. Eighty-two consecutive patients who underwent elective lumbar discectomy by the senior author were identified from 1989 through 1994. Those patients who underwent a primary discectomy with a minimum of 6 months' follow-up were studied. Patients were excluded if a spinal fusion was performed or if a multilevel laminectomy procedure was required. Patients were classified as compensation patients if they were involved in either worker's compensation claims or active litigation at the time of the lumbar discectomy. The compensation group was further divided into three subsets of patients: those involved in active litigation without compensation, those involved in both compensation and litigation, and those pursuing workers' compensation claims without litigation. The control group was comprised of patients who were not in any way involved with compensation or litigation. Outcome assessment and ratings were determined independently by the coauthors, not the primary surgeon. Outcome was based on pain, employment status, analgesic use, and level of activity. Fifty-four patients met the inclusion criteria. Average follow-up for the compensation patients was 40 weeks. Follow-up for the noncompensation patients averaged 51 weeks. Eighty-one percent of our patients in the noncompensation group achieved a good result. Only 1 of 27 patients was categorized as having a poor outcome. Conversely, patients who were actively involved in the compensation and/or litigation process had significantly poorer outcomes, with only 29% of the patients receiving a good outcome evaluation (p = < 0.0002). Legal involvement was associated with poorer outcome in compensation patients (p = < 0.001).

Adult↗

PubMed1997

Osteochondritis dissecans as a cause of developmental dislocation of the radial head.

Osteochondritis dissecans of the capitellum produces an area of focal necrosis that may result in a potentially unstable relationship between the capitellum and the radial head. Seven patients with developmental instability of the radial head secondary to osteochondritis dissecans of the capitellum treated between 1984 and 1995 were studied. All patients were male with an average age of 13 years. The most common symptom was pain with a decrease in range of motion. Patients lacked an average of 24.3 degrees extension. Initial plain radiographs were most helpful for evaluating the relationship of the radial head to the capitellum, and tomography or magnetic resonance imaging were helpful for the detection of loose bodies. The most common direction for instability was posterolateral. Treatment varied from conservative management with nonsteroidal antiinflammatory medication to open reduction and internal fixation of an osteochondral fragment. The average followup was 3.2 years. At latest followup, 11 patients were pain free; however, they lacked an average of 17 degrees extension. Only 2 patients progressed to complete dislocation of the radial head. Developmental instability of the radial head may occur secondary to osteochondritis dissecans of the capitellum. Plain radiographs are sufficient for initial detection and followup. Treatment is determined by the presence of loose bodies and the characteristics of the osteochondral defect. Initial symptoms will resolve; however, lack of extension may persist.

Adolescent↗

PubMed1997

Treatment of syringomyelia associated with arachnoid scarring caused by arachnoiditis or trauma.

The authors conducted a retrospective study of 107 patients treated for syringomyelia associated with arachnoid scarring between 1976 and 1995 at the Departments of Neurosurgery at the Nordstadt Hospital in Hannover, Germany, and the University of California in Los Angeles, California. Twenty-nine patients have not been surgically treated to date because of their stable neurological status. Seventy-eight patients with progressive neurological deficits underwent a total of 121 surgical procedures and were followed for a mean period of 32 (+/- 37) months. All patients demonstrated arachnoid scarring at a level close to the syrinx. In 52 patients the arachnoid scarring was related to spinal trauma, whereas 55 had no history of trauma and developed arachnoid scarring was a result of an inflammatory reaction. Of these, 15 patients had undergone intradural surgery, eight had suffered from spinal meningitis, three had undergone peridural anesthesia, and one each presented with a history of osteomyelitis, spondylodiscitis, and subarachnoid hemorrhage. No obvious cause for the inflammatory reaction resulting in arachnoid scarring could be ascertained for the remaining 26 patients. The postoperative neurological outcome correlated with the severity of arachnoid pathology and the type of surgery performed. Shunting of the syrinx to the subarachnoid, pleural, or peritoneal cavity was associated with recurrence rates of 92% and 100% for focal and extensive scarring, respectively. Successful long-term management of the syrinx required microsurgical dissection of the arachnoid scar and decompression of the subarachnoid space with a fascia lata graft. This operation stabilized the preoperative progressive neurological course in 83% of patients with a focal arachnoid scar. For patients with extensive arachnoid scarring over multiple spinal levels or after previous surgery, clinical stabilization was achieved in only 17% with this technique.

Adult↗

PubMed1996

Surgical results of spinal meningiomas.

We report on 94 spinal meningiomas in 88 patients operated between September 1977 and August 1994 which were followed for up to 13 years (mean 24 +/- 35 months). Complete tumour resection led to postoperative improvement of every preoperative deficit or symptom. En plaque, recurrent, anterior, and low thoracic or lumbar meningiomas were likely to be resected incompletely. Partial tumour removal, arachnoid scarring, primary dural suture, recurrent meningiomas, and male sex were independent factors predisposing to clinical recurrence. Cauterization instead of resection of the tumor matrix was not associated with a higher recurrence rate.

Adolescent↗

PubMed1996

Spinal chordomas--results of treatment over a 17-year period.

Among a series of 511 spinal tumours treated in the Department of Neurosurgery at the Nordstadt Hospital in Hannover, Germany, between September 1977 and August 1994, 23 operations for spinal chordomas in 9 patients (3 females, 6 males) were performed. After an average period of 7 +/- 12 months (2 weeks to 5 years) patients presented at an average age of 45 +/- 17 years with pain (68%), gait ataxia (14%), motor weakness (9%) or sphincter disturbances (9%). A complete resection was achieved in 11 operations and a subtotal tumour removal in 12 instances. After subtotal removal, 5 tumours were treated postoperatively using local high dose radiotherapy (60-70 Gy). Overall, every chordoma recurred with the passage of time unless en-bloc resection of the tumour had been performed. The recurrence-free interval tended to be longer after radiotherapy. Analysis of postoperative results revealed a significant positive effect of radiotherapy for motor function, pain, Karnofsky score, and survival. In conclusion, en-bloc resection should be performed whenever localization and extension of the tumour allow one to do so. Surgery should be followed by local high dose radiotherapy.

Chordoma↗