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Biomedical subjects

R R Lonser

Publications and source records attributed to R R Lonser.

30 records · Page 2Linked to original sources
PubMed1996

Simultaneous bilateral pallidoansotomy for idiopathic dystonia musculorum deformans.

A 17-year-old Russian male with a 9-year diagnosed history of dystonia musculorum deformans manifested as severe tortipelvis, lordosis, and axial and appendicular spastic dystonia, refractory to medical therapy, is reported. This patient underwent a simultaneous bilateral pallidoansotomy with dramatic results. Postoperative evaluation revealed sustained alleviation of all dystonic symptoms and abnormal movements. Rapid recovery of useful strength in all limbs as well as dramatic improvement in coordination occurred. Bilateral posteroventral pallidotomy and pallidoansotomy in the past have proven effective in alleviation of all parkinsonian symptoms, including dyskinesia and dystonia, without the concurrent risk of intransigent side effects associated with bilateral thalamotomy or other stereotactic surgical procedures. Pallidoansotomy may prove to be the treatment of choice for idiopathic torsion dystonia and merits further investigation.

Adolescent↗
PubMed1996

Bypass coaptation procedures for cervical nerve root avulsion.

In the past, patients with cervical spinal nerve root avulsions were resigned to accept a natural crippling from upper extremity neurological deficits. Recently, bypass coaptation procedures have resulted in functional return of denervated muscles after such avulsions, much to the appreciation of patients. Presented are 12 patients with avulsion of cervical spinal nerve roots that form either the brachial plexus upper trunk (n = 7), lower trunk (n = 1), or all three trunks (n = 4). The patients underwent the new bypass coaptation procedures with complete or partial return of motor and sensory function, which otherwise would be totally nonfunctional. The most dramatic results were noted in those patients who underwent operations within 6 weeks of injury. The results of these procedures offer patients a valid therapeutic modality for an enhanced quality of life after cervical nerve root avulsion.

Adult↗
PubMed1995

Combined stereotactic thalamotomy and posteroventral pallidotomy for Parkinson's disease.

Stereotactic thalamotomy has traditionally provided good relief of tremor for patients with intractable tremor-dominant Parkinson's disease. However, bradykinesia, dyskinesia, and rigidity are often less reliably treated with this technique. Although posteroventral pallidotomy (PVP) can alleviate dyskinesias, appendicular bradykinesia, and rigidity, tremor may not be completely ameliorated. We have combined Vim/VOp junction thalamotomy and PVP in 29 patients with severe tremor, rigidity, and bradykinesia. Patients underwent unilateral Vim thalamotomy followed at the same sitting by PVP. The distinct physiological consequences of each procedure were documented by intraoperative electromyography (EMG) and video recording, revealing the effects on both tremor and agonist/antagonist co-contraction. Lack of reciprocal inhibition of antagonistic muscle groups often remained following thalamotomy but was eliminated by subsequent PVP. The complementary therapeutic effects of PVP and Vim thalamotomy may be due to the interruption of different neuronal circuits by the two procedures. The effect of Vim thalamotomy has been attributed to the interruption of the rubrothalamocortical loop. PVP interrupts the outflow of the globus pallidus interna (GPi), which may cause disinhibition of locomotor centers in the mesencephalon and spinal cord. There is no direct interruption of the rubrothalamocortical loop by PVP, explaining why this procedure sometimes exacerbates tremor in certain patients. The combination of the two procedures appears to provide excellent relief of the majority of symptoms in patients suffering from tremor-dominant Parkinson's disease.

Adult↗
PubMed1995

Chronic anterior pallidal stimulation for Parkinson's disease.

We present the case of a 51-year-old female who had a four-year history of Parkinson's disease with severe "on-off' and disabling progression of symptoms on chronic levodopa therapy. After obtaining FDA approval, we implanted a Medtronic deep brain stimulation lead stereotactically into the right anterior pallidum contralateral to her most symptomatologic side. Intra-operative stimulation trials at 100 Hz caused reproducible reversal of akinetic symptoms and simultaneous microelectrode recording of the posteroventral pallidum revealed decreased neural activity during anterior pallidal stimulation. The patient was evaluated pre-operatively and postoperatively using the Hoehn and Yahr Staging Scale, the Unified Parkinson's Disease Rating Scale (UPDRS), videotape, and a computerized data glove. Six months after implantation, the total UPDRS score was decreased from 68 to 8 and Hoehn and Yahr Staging improved from 3.0 to 1.5 during periods of chronic high frequency stimulation. Dramatic improvements in tremor, dystonia, bradykinesia, and akinesia were noted within seconds of stimulator activation and were also objectively measured using a computerized data glove. This case reveals the potential for therapeutic pallidal stimulation for Parkinson's akinetic symptomatology.

Antiparkinson Agents↗
PubMed1995

New pathophysiology of Parkinson's disease revealed by posteroventral pallidotomy.

Since the failure of levodopa therapy to maintain long-term symptom relief in Parkinson's disease, posteroventral pallidotomy has seen a dramatic increase in use and interest. It has significantly reduced both the akinetic and hyperkinetic symptoms of Parkinson's disease while requiring most patients to maintain preoperative levodopa doses. Here we review the clinical results of over 300 posteroventral pallidotomies and pathophysiology of Parkinson's disease in relationship to different neurotransmitters and medical therapy.

Combined Modality Therapy↗
PubMed1995

Stimulation of the globus pallidus in Parkinson's disease.

In 62 patients undergoing posteroventral pallidotomy (PVP) for the treatment of Parkinson's disease, we have demonstrated significant (p < 0.01) elimination of akinetic features and other symptoms during intraoperative stimulation trials in areas anterior to the PVP target (n = 30). Stimulation in anterior pallidal regions frequently resulted in an immediate reversal of akinetic states despite enforced abstinence of medications. The beneficial effects were achieved with as little as 0.25 V at 100 Hz. Stimulation at the PVP target site (n = 32) resulted in insignificant changes (p > 0.05).

Adult↗
PubMed1995

Unilateral versus bilateral simultaneous posteroventral pallidotomy in subgroups of patients with Parkinson's disease.

Despite the bilateral appendicular symptoms of Parkinson's disease, bilateral surgical interventions in the basal ganglia have been shunned because of cognitive and speech disturbances following bilateral thalamotomy. However, we present the uncomplicated results of 25 simultaneous posteroventral pallidotomies and compare their obvious superior control of appendicular symptoms as well as axial symptoms with the results of 25 unilateral posteroventral pallidotomies.

Adult↗
PubMed1995

The results, indications, and physiology of posteroventral pallidotomy for patients with Parkinson's disease.

In the past, stereotactic surgical intervention for Parkinson's disease was considered indicated only in those patients with active motor manifestations that were refractory to pharmacological therapy, manifestations such as tremor, rigidity, dystonia, and dyskinesia. With the reintroduction and refinement of Leksell's posteroventral pallidotomy, both akinetic and hyperkinetic symptoms are now amenable to surgical treatment. We have analyzed the results of 126 patients who underwent either unilateral (n = 58) or bilateral (n = 68) posteroventral pallidotomies. The Unified Parkinson's Disease Rating Scale and Hoehn and Yahr Staging Scale were used for preoperative and postoperative objective assessments. Postoperative follow-up evaluation occurred initially at 1 week and subsequently at intervals between 1 and 12 months (mean = 4.5 months) after surgery. Although individual motor subscores on the Unified Parkinson's Disease Rating Scale were significantly reduced (n = 126, P < or = 0.01), the most dramatic findings were the reversal of akinetic symptoms and the elimination of dyskinesia and profound "off" periods. These clinical results, combined with intraoperative microelectrode records revealing pallidal neuronal hyperactivity, suggest a reconsideration of the pathophysiology of akinesia and point to possible mechanisms of akinesia improvement by posteroventral pallidotomy in some parkinsonian subgroups.

Adult↗
PubMed1994

Contemporaneous bilateral postero-ventral pallidotomy for early onset "juvenile type" Parkinson's disease. Case report.

Early onset "juvenile type" Parkinson's disease is commonly associated with disabling bilateral levodopa-induced dyskinesias. We report here a successful contemporaneous bilateral postero-ventral pallidotomy performed on a 46-year-old male with juvenile type Parkinson's and associated levodopa incited symmetric dyskinesias. A comparison of various surgical alternatives is included. Preoperative and postoperative evaluation, operative method and posteroventral pallidotomy's therapeutic mechanism are presented.

Antiparkinson Agents↗
PubMed1994

Stereotactic pallidotomy results for Parkinson's exceed those of fetal graft.

Fetal graft research and renewed interest in Leksell's postero-ventral pallidotomy (PVP) stimulated reconsideration of surgical therapy for Parkinson's disease (PD), particularly with regard to improving akinetic symptoms previously thought resistant to surgical lesions. Review of our series and other published results of PVP and fetal graft show that PVP has beneficial effects on both akinetic and hyperkinetic symptoms that better the results reported for fetal graft implantation and other conventional stereotactics. Presented are the results of 60 consecutive patients, 55 of whom underwent PVP, and 5 who underwent fetal graft implantation. Using the Unified Parkinson's Disease Rating Scale (UPDRS), we found that PVP gave significant (P < 0.05) reductions in akinetic symptomatology including freezing, arising from a chair, posture, gait, postural instability, and bradykinesia. Fetal graft patients had significant reductions in two akinetic symptoms: bradykinesia and postural instability. PVP's dramatic therapeutic effects on akinesia may be explained by interruption of amplified collateral inhibitory output from the pallidum to brain stem locomotor centers such as the pedunculopontine nucleus, whereas interruption of collaterals to ventral lateral thalamus by PVP may account for the elimination of hyperkinesia. The excellent results of PVP represent a significant advance in the surgical treatment of PD.

Activities of Daily Living↗
PubMed1992

Seroma prevention after modified radical mastectomy.

The most common mastectomy-associated complication is seroma formation. Seromas can be associated with other more serious complications such as skin flap necrosis, delayed wound healing, infection, and lymphedema. The flap tacking procedure that closes the axillary fossa dead space and tacks the mastectomy flaps to the chest wall has been suggested as one potential technique to reduce the incidence of postmastectomy seromas. This institution-wide study of modified radical mastectomies demonstrated a significant decrease (P < 0.0381) in the incidence of seroma when flap tacking was performed. Women who developed a seroma, compared to those who did not, averaged nearly twice as any office visits in the first 2 months after the operation. Distribution of office visits between the seroma patients and nonseroma patients was significant (P < 0.0001). When practiced by several surgeons, the flap tacking procedure 1) reduces postmastectomy seromas and 2) reduces the amount of postoperative patient office visits and care.

Adult↗