Kiril Kiprovski, M.D.

MRI of the distal biceps femoris muscle: normal anatomy, variants, and association with common peroneal entrapment neuropathy
Vieira, Renata La Rocca; Rosenberg, Zehava Sadka; Kiprovski, Kiril
2007 Sep;189(3):549-555, American journal of roentgenology
OBJECTIVE: The objectives of our study were to describe the previously unreported normal MR anatomy of the distal biceps femoris muscle and its relationship with the common peroneal nerve and to present a case in which previously unreported MR evidence of an anatomic variation in the distal biceps femoris muscle was associated with common peroneal entrapment neuropathy. MATERIALS AND METHODS: One hundred consecutive 1.5-T knee MR studies of 97 asymptomatic patients were retrospectively reviewed by two observers in consensus for, first, normal anatomy of the distal biceps femoris muscle; second, anatomic variations of the muscle; and, third, the relationship of the muscle to the common peroneal nerve. Measurements of the distal and posterior extents of the short and long heads of the biceps femoris were performed. An MR study of a symptomatic patient with clinical evidence of common peroneal neuropathy associated with a surgically proven anatomic variation of the distal biceps femoris was reviewed. RESULTS: Two MR anatomic patterns were seen in the asymptomatic patient group: First, in 77 knees (77%), the common peroneal nerve was located within abundant fat posterolateral to the biceps femoris; and, second, in 23 cases (23%), the common peroneal nerve traversed within a narrow fatty tunnel between the biceps femoris and lateral head of the gastrocnemius muscles. There was a positive correlation between the distal and posterior extents of the short head of the biceps femoris muscle and the presence of the tunnel. CONCLUSION: Variations in the posterior and distal extents of the biceps femoris muscle can produce a tunnel in which the common peroneal nerve travels. We also described a case of common peroneal neuropathy secondary to tunnel formation
— id: 73917, year: 2007, vol: 189, page: 549, stat: Journal Article,

Clinically significant placebo analgesic response in a pilot trial of botulinum B in patients with hand pain and carpal tunnel syndrome
Breuer, Brenda; Sperber, Kevin; Wallenstein, Sylvan; Kiprovski, Kiril; Calapa, Angela; Snow, Barry; Pappagallo, Marco
2006 Jan-Feb;7(1):16-24, Pain medicine
OBJECTIVE: We conducted a pilot trial to assess the effect of botulinum toxin B on palmar pain and discomfort in carpal tunnel syndrome (CTS) patients. Design. Randomized, double-blind, placebo-controlled. PATIENTS: Twenty ambulatory CTS patients. Intervention. Botulinum toxin B or placebo injections into three hypothenar muscles anatomically linked or attached to the carpal tunnel and its tentorium, that is, the Opponens Digiti Minimi and Flexor Digiti Minimi, located with electromyography (EMG), and the Palmaris Brevis Muscle, anatomically located without EMG. SETTING: New York City hospital. OUTCOME MEASURES: Outcomes were measured with numeric ratings, with higher scores indicating worse outcomes. Daily, subjects recorded their 0-10 numeric ratings of overall pain levels and pain-related sleep disturbances. During weekly telephone calls, they reported their 0-10 ratings for overall pain, pain-related sleep disturbance, and CTS-related tingling during the night and day as experienced over the preceding 24 hours. For each of four clinic visits, we averaged each subject's ratings of nine quality of life indicators from the West Haven-Yale Multidimensional Pain Inventory (WHYMPI), each measured on a 0-6 numeric scale. RESULTS: Over the 13-week trial, compared to baseline scores, the following outcomes predominantly showed decreases of statistical significance (P < or = 0.050) or borderline significance (0.050 < P < or = 0.10) for weeks 2 through 8: overall pain per daily diary entries and per weekly telephone reports, and pain-related sleep disturbance in the placebo group per phone report and in the botulinum toxin B group per diary report. CTS painful night tingling and day tingling, as well as the average scores of the WHYMPI quality of life indicators, showed improvements with statistical or borderline significance for almost each follow-up week. Between-group analyses, however, demonstrated that at each follow-up week, there was no statistically significant difference between the two study groups regarding changes from baseline in any study outcome. CONCLUSION: Botulinum toxin B is not dramatically superior to placebo for the relief of CTS symptoms. Possible explanations of the improvements in each study group are explored
— id: 95715, year: 2006, vol: 7, page: 16, stat: Journal Article,

MR imaging features of radial tunnel syndrome: initial experience
Ferdinand, Brett D; Rosenberg, Zehava Sadka; Schweitzer, Mark E; Stuchin, Steven A; Jazrawi, Laith M; Lenzo, Salvatore R; Meislin, Robert J; Kiprovski, Kiril
2006 Jul;240(1):161-168, Radiology
PURPOSE: To retrospectively assess magnetic resonance (MR) imaging features of radial tunnel syndrome. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived for the retrospective HIPAA-compliant study. MR images of 10 asymptomatic volunteers (six men, four women; mean age, 30 years) and 25 patients (11 men, 14 women; mean age, 49 years) clinically suspected of having radial tunnel syndrome were reviewed for morphologic and signal intensity alterations of the posterior interosseous nerve and adjacent soft-tissue structures. MR images of the asymptomatic volunteers were reviewed to establish the normal appearance of the radial tunnel. MR images of the symptomatic patients were evaluated for the following: signal intensity alteration and morphologic alteration of the posterior interosseous nerve; the presence of mass effect on the posterior interosseous nerve such as the presence of bursae, a thickened leading edge of the extensor carpi radialis brevis, or prominent radial recurrent vessels; signal intensity alteration within the depicted forearm musculature such as edema or atrophy; and signal intensity changes at the origin of the common extensor and common flexor tendons, which would suggest a diagnosis of epicondylitis. RESULTS: All images of volunteers demonstrated normal morphology and signal intensity within the posterior interosseous nerve and adjacent soft tissues. Two volunteers had borderline thickening of the leading edge of the extensor carpi radialis brevis. Thirteen patients (52%) had denervation edema or atrophy within muscles (supinator and extensors) innervated by the posterior interosseous nerve. One patient had isolated pronator teres edema. Seven (28%) patients had the following mass effects along the posterior interosseous nerve: thickened leading edge of the extensor carpi radialis brevis (n = 4), prominent radial recurrent vessels (n = 1), schwannoma (n = 1), or bicipitoradial bursa (n = 1). The rest of the patients had either normal MR imaging findings (n = 4) or lateral epicondylitis (n = 2). CONCLUSION: Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome
— id: 66465, year: 2006, vol: 240, page: 161, stat: Journal Article,

Neurophysiological refinement of subthalamic nucleus targeting
Sterio, Djordje; Zonenshayn, Martin; Mogilner, Alon Y; Rezai, Ali R; Kiprovski, Kiril; Kelly, Patrick J; Beric, Aleksandar
2002 Jan;50(1):58-67, Neurosurgery
OBJECTIVE: Advances in image-guided stereotactic surgery, microelectrode recording techniques, and stimulation technology have been the driving forces behind a resurgence in the use of functional neurosurgery for the treatment of movement disorders. Despite the dramatic effects of deep brain stimulation (DBS) techniques in ameliorating the symptoms of Parkinson's disease, many critical questions related to the targeting, effects, and mechanisms of action of DBS remain unanswered. In this report, we describe the methods used to localize the subthalamic nucleus (STN) and we present the characteristics of encountered cells. METHODS: Twenty-six patients with idiopathic Parkinson's disease underwent simultaneous, bilateral, microelectrode-refined, DBS electrode implantation into the STN. Direct and indirect magnetic resonance imaging-based anatomic targeting was used. Cellular activity was analyzed for various neurophysiological parameters, including firing rates and interspike intervals. Physiological targeting confirmation was obtained by performing macrostimulation through the final DBS electrode. RESULTS: The average microelectrode recording time for each trajectory was 20 minutes, with a mean of 5.2 trajectories/patient. Typical trajectories passed through the anterior thalamus, zona incerta/fields of Forel, STN, and substantia nigra-pars reticulata. Each structure exhibited a characteristic firing pattern. In particular, recordings from the STN exhibited an increase in background activity and an irregular firing pattern, with a mean rate of 47 Hz. The mean cell density was 5.6 cells/mm, with an average maximal trajectory length of 5.3 mm. Macrostimulation via the DBS electrode yielded mean sensory and motor thresholds of 4.2 and 5.7 V, respectively. CONCLUSION: The principal objectives of microelectrode recording refinement of anatomic targeting are precise identification of the borders of the STN and thus determination of its maximal length. Microelectrode recording also allows identification of the longest and most lateral segment of the STN, which is our preferred target for STN DBS electrode implantation. Macrostimulation via the final DBS electrode is then used primarily to establish the side effect profile for postoperative stimulation. Microelectrode recording is a helpful targeting adjunct that will continue to facilitate our understanding of basal ganglion physiological features
— id: 33634, year: 2002, vol: 50, page: 58, stat: Journal Article,

Polyglucosan body myopathy
Carniciu, S; Kiprovski, K; Levine, DN; ZagZag, D; Bronfin, L; Kolodny, EH
2000 SEP ;48(3):440-440, Annals of neurology
— id: 74939, year: 2000, vol: 48, page: 440, stat: Journal Article,

The use of motor evoked potentials in the diagnosis of psychogenic quadriparesis. A case study
Morota N; Deletis V; Kiprovski K; Epstein F; Abbott R
1994 ;20(3):203-206, Pediatric neurosurgery
We present a case illustrating the usefulness of motor evoked potentials (MEPs) in differentiating psychogenic from organic postoperative paralysis. Discussed is a 12-year-old girl who underwent surgery for the repair of a recurrent syringomyelia. On the 6 day after a proximal revision of her syringoperitoneal shunt she returned to the hospital with deep quadriparesis, bowel and bladder incontinence, and complaining of severe headache. An MRI scan showed the syrinx to be collapsed, and removal of the shunt had no impact on her clinical symptoms. Repeat somatosensory evoked potentials (SEPs) showed no change in comparison to those obtained at the end of her preceding surgery. MEPs were normal for the lower extremities, a finding which is inconsistent with a severe upper motor neuron lesion. She was diagnosed with psychogenic paralysis, and fully recovered within 1 month. We propose that a neurophysiological evaluation including MEPs is useful in the differential diagnosis of psychogenic and organic motor weakness
— id: 6463, year: 1994, vol: 20, page: 203, stat: Journal Article,

The influence of halothane, enflurane, and isoflurane on motor evoked potentials
Deletis V; Kiprovski K; Morota N
1993 Jul;33(1):173-174, Neurosurgery
— id: 24241, year: 1993, vol: 33, page: 173, stat: Journal Article,

Transcranial electrical and magnetic motor cortex stimulation: studies in intact man
Zidar J; Zgur T; Kiprovski K
1989 ;38(4):271-283, Neurologija
The new method of transcranial electrical and magnetic brain stimulation was tested in 41 normal subjects. Stimulation on the scalp excites corticospinal neurones in the motor cortex while stimulation over the spine excites spinal nerve roots. The difference between EMG response latencies after both stimulations represents conduction in the central motor pathways and is called central motor latency (CML). The aim of out experiments was to investigate certain methodological aspects of the technique in order to standardize the procedure. Recordings were done from slightly contracted abductor digiti minimi and tibialis anterior muscles after electrical stimulation on the scalp and from the relaxed and contracted abductor digiti minimi and biceps brachii muscles after magnetic brain stimulation. Stimulation over the spine (C7/T1 interspace in case of upper limb muscles stimulation and T12/L1 interspace in case of tibialis anterior stimulation) was always electrical. Using a rather weak non-commercial magnetic stimulator we were not able to activate lower limb muscles, neither we succeeded to evoke responses from the relaxed arm muscles in all subjects. Electrical scalp stimulation proved successful in all cases. Muscle response after cortical stimulation in contracting muscles and shorter latencies and provided more accurate estimate of conduction time in the central motor pathways than responses in the relaxed muscles. Latencies should be measured from several superimposed responses and not from averaged ones. The intensity of stimulation over the neck did not affect CML. We nevertheless suggest that the strongest stimulus intensities should not be used in order to avoid CML overestimation
— id: 24242, year: 1989, vol: 38, page: 271, stat: Journal Article,