Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Patrick P. Han is active.

Publication


Featured researches published by Patrick P. Han.


Neurosurgery | 2004

Preliminary experience using the Neuroform stent for the treatment of cerebral aneurysms.

David Fiorella; Felipe C. Albuquerque; Patrick P. Han; Cameron G. McDougall

INTRODUCTIONThe Neuroform microstent—a flexible, self-expandable, microcatheter-delivered, nitinol stent designed for the treatment of cerebral aneurysms—was recently approved for use in patients. We present the results of our initial experience in using the Neuroform stent to treat patients with cerebral aneurysms, with an emphasis on potential applications, technical aspects of deployment, and associated intra- and periprocedural complications. METHODSThe records of all patients treated with the Neuroform stent were entered prospectively into a database. We assessed the clinical history, indications for stent use, aneurysm dimensions, and technical details of the procedures, including any difficulties with stent placement and/or deployment, degree of aneurysm occlusion, and complications. RESULTSDuring a 5-month period, 19 patients with 22 aneurysms were treated with the Neuroform stent. Twenty-five stents were deployed. Five patients had multiple stents placed. Five patients had ruptured aneurysms at the time of treatment. The indications for use were broad-necked aneurysms (n = 13; average neck length, 5.1 mm; average aneurysm size, 9 mm), fusiform or dissecting aneurysms (n = 3), salvage and/or bailout (n = 1), and giant aneurysms (n = 2). Technical problems included difficulty in deploying the stent (n = 6), inability to deploy the stent (n = 1), stent displacement (n = 2), inadvertent stent deployment (n = 1), and coil stretching (n = 1). Twenty-one of the 22 aneurysms were treated. Four aneurysms were stented without additional treatment, and 17 aneurysms were stented and coiled. Of the coiled aneurysms, complete or nearly complete (more than 95%) occlusion was achieved in 6 aneurysms, and partial occlusion was achieved in 11. Two clinically significant adverse events occurred, both of which were sequelae of periprocedural thromboembolic complications. One patient died after thrombolysis was attempted. The other patient made an excellent functional recovery after undergoing successful thrombolysis of a thrombosed basilar artery stent. CONCLUSIONThe Neuroform stent is a useful device for the treatment of patients with aneurysms that may not otherwise be amenable to endovascular therapy. In the majority of cases, the stent can be deployed accurately, even within the most tortuous segments of the cerebral vasculature. Although delivery and deployment may be technically challenging, clinically significant complications are uncommon.


Neurosurgery | 2003

Multimodality treatment of giant intracranial arteriovenous malformations

Steven D. Chang; Mary L. Marcellus; Michael P. Marks; Richard P. Levy; Huy M. Do; Gary K. Steinberg; Robert H. Rosenwasser; L. Dade Lunsford; Patrick P. Han; Robert F. Spetzler; H. Hunt Batjer; Warren R. Selman

OBJECTIVE Giant arteriovenous malformations (AVMs) (i.e., those greater than 6 cm at maximum diameter) are difficult to treat and often carry higher treatment morbidity and mortality rates than do smaller AVMs. In this study, we reviewed the treatment, angiographic results, and clinical outcomes in 53 patients with giant AVMs who were treated at Stanford between 1987 and 2001. METHODS The patients selected included 20 males (38%) and 33 females (62%). Their presenting symptoms were hemorrhage (n = 20; 38%), seizures (n = 18; 34%), headaches (n = 8; 15%), and progressive neurological deficits (n = 7; 13%). One patient was in Spetzler-Martin Grade III, 9 were in Spetzler-Martin Grade IV, and 43 were in Spetzler-Martin Grade V. The mean AVM size was 6.8 cm (range, 6-15 cm). AVM venous drainage was superficial (n = 7), deep (n = 20), or both (n = 26). At presentation, 31 patients (58%) were graded in excellent neurological condition, 17 were graded good (32%), and 5 were graded poor (9%). RESULTS The patients were treated with surgery (n = 27; 51%), embolization (n = 52; 98%), and/or radiosurgery (n = 47; 89%). Most patients received multimodality treatment with embolization followed by surgery (n = 5), embolization followed by radiosurgery (n = 23), or embolization, radiosurgery, and surgery (n = 23). Nineteen patients (36%) were completely cured of their giant AVMs, 90% obliteration was achieved in 4 patients (8%), less than 90% obliteration was achieved in 29 patients (55%) who had residual AVMs even after multimodality therapy, and 1 patient was lost to follow-up. Of the 33 patients who either completed treatment or were alive more than 3 years after undergoing their most recent radiosurgery, 19 patients (58%) were cured of their AVMs. The long-term treatment-related morbidity rate was 15%. The clinical results after mean follow-up of 37 months were 27 excellent (51%), 15 good (28%), 3 poor (6%), and 8 dead (15%). CONCLUSION The results in this series of patients with giant AVMs, which represents the largest series reported to date, suggest that selected symptomatic patients with giant AVMs can be treated successfully with good outcomes and acceptable risk. Multimodality treatment is usually necessary to achieve AVM obliteration.


Neurosurgery | 2002

Treatment of giant intracranial aneurysms with saphenous vein extracranial-to-intracranial bypass grafting: Indications, operative technique, and results in 29 patients

Jafar J. Jafar; Stephen M. Russell; Henry H. Woo; Patrick P. Han; Robert F. Spetzler; Laligam N. Sekhar; Ramin Rak; Arthur L. Day; Stephen B. Lewis; H. Hunt Batjer

OBJECTIVE The treatment of giant intracranial aneurysms is a challenge because of the limitations and difficulty of direct surgical clipping and endovascular coiling. We describe the indications, surgical technique, and complications of saphenous vein extracranial-to-intracranial bypass grafting followed by acute parent vessel occlusion in the management of these difficult lesions. METHODS Between January 1990 and December 1999, 29 patients with giant intracranial aneurysms underwent 30 saphenous vein bypass grafts followed by immediate parent vessel occlusion. There were 11 men and 18 women with a mean follow-up period of 62 months. Twenty-five patients harbored aneurysms involving the internal carotid artery, 2 had middle cerebral artery aneurysms, and 2 had aneurysms in the basilar artery. Serial cerebral or magnetic resonance angiograms were obtained to assess graft patency and aneurysm obliteration. RESULTS All 30 aneurysms were excluded from the cerebral circulation, with 28 vein grafts remaining patent. Two patients had graft occlusions: one because of poor runoff and the other because of misplacement of a cranial pin during a bypass procedure on the contralateral side. Other surgical complications included one death from a large cerebral infarction, homonymous hemianopsia from thrombosis of an anterior choroidal artery after internal carotid artery occlusion, and temporary hemiparesis from a presumed perforator thrombosis adjacent to a basilar aneurysm. CONCLUSION With appropriate attention to surgical technique, a saphenous vein extracranial-to-intracranial bypass followed by acute parent vessel occlusion is a safe and effective method of treating giant intracranial aneurysms. A high rate of graft patency and adequate cerebral blood flow can be achieved. Thrombosis of perforating arteries caused by altered blood flow hemodynamics after parent vessel occlusion may be a continuing source of complications.


Neurosurgery | 2002

Thoracoscopic approaches to the thoracic spine: experience with 241 surgical procedures.

Patrick P. Han; Kathy J. Kenny; Curtis A. Dickman

INTRODUCTION Microsurgical thoracoscopic approaches to the thoracic spine allow access to the spinal cord, spinal nerves, disc spaces, vertebral bodies, paravertebral soft tissues, and sympathetic chain with minimal invasiveness. METHODS Between January 1994 and January 2000, 241 thoracoscopic procedures were performed: 164 thoracic sympathectomies, 60 discectomies, 5 neurogenic tumor resections, 8 corpectomies and spinal reconstructions, 2 anterior releases, and 2 biopsies. Cases were reviewed to evaluate the efficacy, surgical results, and complications of the thoracoscopic procedures. RESULTS An adequate sympathectomy was achieved in all 164 sympathectomies. There was 100% relief of palmar and 95% relief of axillary hyperhidrosis. Reflex sympathetic dystrophy responded poorly to sympathectomy with recurrent pain. Thoracoscopic discectomy achieved complete decompression in 98% of patients. Gross total tumor resection was achieved in all five paraspinal neurogenic tumors. There was no operative mortality. Morbidity compared favorably with open surgical approaches to the thoracic spine. CONCLUSION Thoracoscopic spinal surgery is an effective technique that provides full, direct access to the ventral thoracic spine. Its morbidity rate appears to be lower than that associated with open thoracotomy. It improves patient comfort and cosmetic results and shortens recovery. This technique has become the authors’ surgical approach of choice for removing benign intrathoracic paraspinal neurogenic tumors and central herniated thoracic discs and for performing biopsies and thoracic sympathectomies. The senior author still prefers open surgical approaches for most thoracic corpectomies and spinal reconstruction procedures.


Neurosurgery | 2004

Microsurgical treatment of basilar apex aneurysms: perioperative and long-term clinical outcome.

Alan P. Lozier; Grace H. Kim; Robert R. Sciacca; E. Sander Connolly; Robert A. Solomon; H. Hunt Batjer; Gary K. Steinberg; Ricardo A. Hanel; Elad I. Levy; L. Nelson Hopkins; Patrick P. Han; Robert F. Spetzler; Michael T. Lawton

OBJECTIVEWe sought to analyze the perioperative and long-term clinical outcome data for patients with microsurgically treated basilar apex aneurysms. METHODSWe identified 98 consecutively treated basilar apex aneurysms in patients prospectively enrolled in a cerebral aneurysm database. RESULTSFifty patients presented with subarachnoid hemorrhage, and 19 aneurysms were giant. Eighty-four of 98 aneurysms were directly clipped. Surgical morbidity was 19.4% for the entire cohort and 8.8% for the unruptured, nongiant subgroup. The most common complication resulting in long-term morbidity was perforator injury. Sixty-seven percent of patients with clipped aneurysms were independent at discharge; this fraction increased to 79.0% at the 3-month follow-up examination. Good long-term outcomes (modified Rankin Scale score ≤2) were achieved in 56 (70%) of 80 cases. The mean Barthel Index of surviving patients was 95.8 ± 15.0 (median = 100, n = 66). Patients with unruptured, nongiant lesions fared considerably better than patients in other cohorts. Ninety-three percent of this subgroup was independent at discharge; this fraction increased to 100% at the 3-month follow-up examination (n = 27). In univariate analyses, poor clinical grade, giant aneurysm size, major operative complications, and operations performed early in the series were associated with worse outcomes. In the multivariate analysis, unruptured giant aneurysm status was found to confer a tremendous risk for poor outcome (risk ratio, 80.0; 95% confidence interval, 8.0–800.7; P < 0.01). Surviving patients were observed for a mean clinical follow-up period of 7.4 ± 3.7 years. The annual rate of postoperative subarachnoid hemorrhage was 0.18% for all clipped aneurysms and 0% for completely clipped lesions. CONCLUSIONIn comparison to data from the existing literature regarding Guglielmi detachable coil embolization of basilar apex aneurysms, the data presented suggest that surgical clipping should be an important component of a multimodality approach to the treatment of patients with basilar apex aneurysms.


Neurosurgery | 2002

Biportal thoracoscopic sympathectomy: surgical techniques and clinical results for the treatment of hyperhidrosis.

Patrick P. Han; Oren N. Gottfried; Kathy J. Kenny; Curtis A. Dickman

OBJECTIVE To describe a bilateral thoracoscopic sympathectomy procedure, using a biportal approach, for the treatment of severe hyperhidrosis. METHODS Between May 1996 and September 2000, 103 consecutive patients underwent thoracoscopic sympathectomy procedures to treat bilateral hyperhidrosis (206 procedures). Operative results, complications, and patient satisfaction were determined by reviews of hospital and office charts and by follow-up assessments in the outpatient clinic. Long-term results were determined with clinical examinations, follow-up office visits, and follow-up questionnaires. RESULTS Ninety-three patients presented with primary palmar hyperhidrosis, eight with primary axillary hyperhidrosis, and two with primary craniofacial hyperhidrosis. Rates of complete resolution in the primary area affected were 100% in palmar and craniofacial cases and 75% in axillary cases. The average length of hospitalization was 1.06 days, and 96 patients (93.2%) were discharged on or before the end of the first postoperative day. Of 59 patients (57.3%) who developed compensatory hyperhidrosis, only 11 patients (10.7%) reported that it was bothersome and none considered it disabling. All postoperative complications were transient; five patients experienced unilateral Horner’s syndrome, three patients experienced intercostal neuralgia, and two patients required a chest tube after surgery because of a pneumothorax. CONCLUSION Thoracoscopic sympathectomy using a biportal approach effectively treats hyperhidrosis and is associated with short hospital stays, high patient satisfaction rates, and low rates of compensatory hyperhidrosis or other complications.


Canadian Journal of Neurological Sciences | 2002

Carotid dissection: technical factors affecting endovascular therapy.

Felipe C. Albuquerque; Patrick P. Han; Robert F. Spetzler; Joseph M. Zabramski; Cameron G. McDougall

BACKGROUND AND PURPOSE To delineate factors associated with the successful endovascular treatment of extracranial carotid dissections, the authors review their management of 13 cases. METHODS The records of 12 patients with 13 dissections were assessed with reference to mechanism of dissection, preoperative symptoms, presence of a pseudoaneurysm, treatment success, and etiology of treatment failure. Patients were followed prospectively and included six men and six women, ranging in age from 27 to 62 years. RESULTS Angioplasty and stenting were performed successfully in 11 of 13 procedures (10 of 12 patients). Follow-up in these 10 patients demonstrated excellent patency through the stented segment in nine of the 11 treated vessels. Two patients, both of whom suffered their original dissection as a result of endarterectomy, required further angioplasty and stenting for stenosis outside the previously treated arterial segment. Regarding the treatment failures, a stent deployment device could not navigate a tortuous loop in one, while a microwire could not be advanced beyond a pseudoaneurysm in the second. Six patients had pseudoaneurysms, four of which were treated only with stenting across the dissected arterial segment. All pseudoaneurysms treated in this fashion resolved. No permanent complications occurred as a result of endovascular therapy. CONCLUSIONS Angioplasty and stenting can be performed safely to manage carotid dissection. A pseudoaneurysm or tortuous anatomy can preclude therapy although the former typically resolves if angioplasty and stenting are feasible. Dissections secondary to endarterectomy may be associated with a higher rate of restenosis after stenting and may require further treatment.


Neurosurgery | 2001

Anterior Cervical Discectomy

Volker K. H. Sonntag; Patrick P. Han; A. Giancarlo Vishteh

Anterior cervical discectomy is performed for a variety of reasons. The most common is a degenerative disease that induces an osteophyte or a herniated nucleus pulposus that then causes radiculopathy or myelopathy (1, 3). The operation is usually straightforward but has multiple pitfalls and nuances (2). This article presents the senior author’s (VKHS’s) surgical technique for anterior cervical discectomy. Once conservative treatment for cervical radiculopathy, myelopathy, or both, has failed, surgical intervention is indicated. Depending on the location of the compression, the amount of axial pain, and the lordosis of the cervical spine, an anterior or posterior approach is used. The anterior approach for a single-level discectomy is described below. In the operating room, the patient must not be hyperextended during intubation. Somatosensory evoked potentials are routinely monitored. The patient is placed supine with the neck slightly hyperextended. The head is not turned. The Caspar operating table attachment is used to help visualize the lower cervical spine on either plain radiographs or fluoroscopy. The Caspar table attachment also allows slight hyperextension of the neck. The neck bar is placed under the lower cervical and upper thoracic areas to avoid undue pressure on the cervical spine (Fig. 1).


Journal of Neurosurgery | 1999

Subdural hematoma from a Type I spinal arteriovenous malformation: Case report

Patrick P. Han; Nicholas Theodore; Randall W. Porter; Paul W. Detwiler; Michael T. Lawton; Robert F. Spetzler

The authors report a patient in whom a subdural hematoma developed from a Type I spinal arteriovenous malformation (AVM). The patient became symptomatic with back pain, and magnetic resonance imaging revealed a spinal subdural hematoma. Selective spinal angiography, however, failed to demonstrate a pathological process. The patient underwent exploratory laminoplasty that revealed a subdural extraarachnoid hematoma with an underlying Type I spinal AVM, which was surgically obliterated. The patient recovered completely. Subdural hematomas that affect the spine are rare. Although a negative result was obtained using selective spinal angiography, exploratory surgery should be considered for the evacuation of a subdural hematoma and possibly for the definitive treatment of a spinal AVM.


Neurosurgery | 2005

Preserving Olfactory Function in Anterior Craniofacial Surgery through Cribriform Plate Osteotomy Applied in Selected Patients

Iman Feiz-Erfan; Patrick P. Han; Robert F. Spetzler; Eric M. Horn; Jeffrey D. Klopfenstein; Louis J. Kim; Randall W. Porter; Stephen P. Beals; Salvatore C. Lettieri; Edward F. Joganic

OBJECTIVE: Olfaction is often sacrificed to gain access to the cranial base in anterior craniofacial surgery. We describe the long-term results of olfactory function in patients who underwent anterior craniofacial surgery and a cribriform plate osteotomy to preserve olfaction. METHODS: Between 1992 and 2004, 28 patients underwent 29 cribriform plate osteotomies in an attempt to preserve olfaction during anterior craniofacial surgery performed through modified extended transbasal approaches. Patients’ charts and office notes were reviewed retrospectively. Formal olfactory testing was available in 5 patients, but most data were based on patients’ subjective reports of olfaction. Olfactory preservation was defined by the subjective ability to detect fumes such as coffee, chocolate, roses, and orange juice regardless of the intensity of the sensation. Follow-up was based on phone calls to patients. RESULTS: Four patients were lost to follow-up and excluded. Therefore, follow-up was available in 24 patients after 25 procedures. On the basis of patients’ subjective reports, olfaction was spared in 22 patients after 23 procedures (92%) and was confirmed objectively in the five patients formally tested. After surgery, only two patients were anosmic. CONCLUSION: Olfaction can be preserved in selected patients undergoing anterior craniofacial surgery. At least 1 cm of nasal mucosa should remain attached to the cribriform plate, which can be achieved by including the nasal bone in the osteotomy of the orbital bar. A medial orbital canthopexy is therefore necessary after these procedures.

Collaboration


Dive into the Patrick P. Han's collaboration.

Top Co-Authors

Avatar

Robert F. Spetzler

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Randall W. Porter

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Iman Feiz-Erfan

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Cameron G. McDougall

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Felipe C. Albuquerque

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Francisco A. Ponce

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Curtis A. Dickman

St. Joseph's Hospital and Medical Center

View shared research outputs
Top Co-Authors

Avatar

Paul W. Detwiler

Barrow Neurological Institute

View shared research outputs
Top Co-Authors

Avatar

Edward F. Joganic

Barrow Neurological Institute

View shared research outputs
Top Co-Authors

Avatar

Joseph M. Zabramski

St. Joseph's Hospital and Medical Center

View shared research outputs
Researchain Logo
Decentralizing Knowledge