Herbert Silverstein

Retrolabyrinthine Surgery: A Direct Approach To The Cerebellopontine Angle

The direct route to the cerebellopontine (CP) angle through the ear (retrolabyrinthine approach) represents a significant advance in neuro-otologic surgery. After incising the dura between the endolymphatic sac and the lateral venous sinus, a self-retaining retractor is used to collapse the lateral sinus, which provides a wide exposure of the CP angle, with visualization of the 5th through 11th cranial nerves. The retrolabyrinthine approach is a safe and direct route to the CP angle and has advantages over the suboccipital approach. Vestibular neurectomy through the retrolabyrinthine approach is the most frequently performed procedure and has replaced middle fossa vestibular neurectomy in our practice.

Direct Round Window Membrane Application of Gentamicin in the Treatment of Meniere's Disease

OBJECTIVE: To evaluate the effectiveness of the round window membrane (RWM) Gelfoam gentamicin technique in patients with Menieres disease who were unresponsive to medical management or in whom surgical therapy failed. STUDY DESIGN: Protocol 1, single intratympanic gentamicin infusion; protocol 2 (the best method), 2 infusions, 5 days apart with reevaluation at 1 month; and protocol 3, multiple infusions 1 to 4 weeks apart. PATIENTS: In total, 32 patients (19 male, 13 female) were enrolled in the study. The mean age was 65 years (range 34 to 94 years). Seven of these patients were surgical salvage cases. INTERVENTIONS: Laser-assisted otoendoscopy with a 1.7-mm otoendoscope (Smith-Nephew Richards, Memphis, TN) was performed first. If the RWM was obscured by mucosa or adhesions, these were cleared before placing a 2 × 3 mm piece of dry Gelfoam against the RWM. Buffered gentamicin (26.7 mg/mL) was then injected into the middle ear (0.2 to 0.3 mL). RESULTS: Overall, vertigo was controlled in 75% of the patients after the completion of the treatment, with subtotal vestibular ablation in two thirds of patients. Hearing was preserved in 90% of the patients (within 15 dB pure-tone average or 15% speech discrimination score), tinnitus improved in 48%, and aural pressure improved in 62.5%.

Retrolabyrinthine vestibular neurectomy.

Vestibular neurectomy performed through the middle fossa or retrolabyrinthine approach is an effective method of denervating the labyrinth while preserving residual hearing. In the authors’ opinion, the retrolabyrinthine approach is easier to perform, takes less time, and places the facial nerve in less jeopardy than the middle fossa procedure. The results of 26 cases of retrolabyrinthine vestibular neurectomy followed from six to 26 months indicate an 85% (22/26) cure rate of vertigo and a 79% (21/26) rate of hearing unchanged or improved.

Cochlear and vestibular gross and histologic anatomy (as seen from postauricular approach).

The otologic surgeon must have a clear understanding of the anatomy of the seventh and eighth cranial nerves from the labyrinth to the brain stem, as seen from the postauricular approach. The surgical anatomy of the seventh and eighth cranial nerves was studied in 64 transcochlear eighth-nerve sections and 33 retrolabyrinthine vestibular neurectomies. Analysis indicates the nerves rotate 90 degrees in their course from the ear to the brain. The key relationship is that the cochlear nerve is always the most inferior, rotating from anterior (medial) near the labyrinth to posterior (lateral) near the brain stem. The seventh (facial) nerve rotates from anterosuperior (medial superior) near the labyrinth to anteroinferior (medial inferior) near the brain stem. The seventh nerve is easily seen in the transcochlear approach and hidden from view in the retrolabyrinthine approach. Twenty-seven fixed nerve specimens were examined with an operating microscope before being prepared for sectioning. In 73% (19 of 26) a cleavage plane was seen on the lateral aspect of the eighth nerve (that portion of the nerve facing the surgeon in the retrolabyrinthine approach).

Use of Streptomycin Sulfate in the Treatment of Meniere's Disease

Streptomycin sulfate has been known to be ototoxic since its use in the treatment of tuberculosis. This report describes 10 years of experience in the treatment of Menieres disease with streptomycin. Streptomycin has been used in (1) classical Schuknecht ablation of the vestibular system in bilateral Menieres disease; (2) classical Schuknecht ablation of the vestibular system in unilateral Menieres disease in the only hearing ear; (3) intratympanic streptomycin in the treatment of unilateral Menieres disease; and (4) low-dose intramuscular streptomycin as outpatient treatment in unilateral Menieres disease. The results of bilateral vestibular ablation were similar to Schuknechts and others. Patients developed profound ataxia with a wide-based gait and oscillopsia, which improved rapidly over a period of months. Approximately 30% experienced significant improvement in hearing, which usually deteriorated again after several months. All patients were relieved of vertigo. Patients with unilateral Menieres disease in the only hearing ear responded as did the bilateral cases. Hearing in the only hearing ear was preserved in all cases. Low-dose subototoxic streptomycin as outpatient treatment offers promise in some cases for relieving attacks of Menieres disease while improving hearing without producing the temporary disabling effects of ataxia and oscillopsia. Streptomycin and similar drugs that may reduce the production of endolymph may eventually be the treatment of choice in Menieres disease.

Partial or Total Eighth Nerve Section in the Treatment of Vertigo

Partial vestibular (singular) neurectomy under general anesthesia through a postauricular approach is an effective method of relieving incapacitating benign positional vertigo, as is the case in 14 of 16 patients (87%) so treated. Middle fossa vestibular neurectomy appears to be a worthwhile procedure to deinnervate the peripheral vestibular system while preserving hearing. The results of 27 middle fossa vestibular neurectomies indicate relief of vertigo in 85% of the patients. The results of treatment on 44 patients undergoing transmeatal-cochleovestibular neurectomy indicated that vertigo was relieved in 19 of 23 (82%) with Menieres disease and Improved in 50% of the patients with poststapedectomy vertigo and sensorineural hearing loss. Tinnitus was cured or markedly improved in 80% of the patients with Menieres disease and 70% of the patients with poststapedectomy sensorineural hearing loss and tinnitus. The transmeatal-transcochlear approach to the internal auditory canal offers advantages over the transmeatal labyrinthectomy or translabyrinthine approach to the internal auditory canal.

Analysis of Surgical Procedures in Patients with Vertigo

The majority of patients with vertigo secondary to inner ear problems can be cured by surgery (80%). The results after neurectomy procedures such as cochleovestibular neurectomy or vestibular neurectomy appear to be much better (85%) than after the endolymphatic subarachnoid shunt procedure (70%). If hearing is worth saving, a conservative procedure should be used first in an effort to preserve the patients hearing. If this fails, a cochleovestibular neurectomy will usually resolve the problem. At present we are using the retrolabyrinthine vestibular neurectomy as a primary procedure for Menieres disease, reserving the cochleovestibular neurectomy for those in whom the vestibular neurectomy failed. In elderly patients it appears the Schuknecht cochleosacculotomy may have promise as a first procedure for control of vertigo.

Silverstein lateral venous sinus retractor.

A SELF-RETAINING retractor has been devised to collapse the skeletonized lateral venous sinus during surgery of the posterior fossa through the retrolabyrinthine or translabyrinthine approach. This retractor has two parts, acurved Wietlander with a length of 6% in and an adjustable malleable curved retractor blade (Fig 1 and 2). A wing nut mounted on the Wietlander allows the retractor blade to slide forward and backward and when tightened secures the blade in position. After the postauricular incision is made, the Wietlander is used (without the malleable blade) to expose the mastoid cortex. The mastoidectomy is completed skeletonizing the lateral venous sinus and the malleable blade is inserted and pulled backward to collapse the lateral venous sinus. The wing nut is tightened to secure the malleable blade. The dura is incised between the lateral venous sinus and the endolymphatic sacwith a No. 59S beaver blade. The endolymphatic sac is retracted forward and upward over the labyrinth and held in place with two self-retaining 4-0 silk sutures. Mannitol, 1.5 gm/kg, is given at the onset of the procedure which greatly reduces the size of the cerebellum. After the cerebral spinal fluid is aspirated from the cerebellopontine angle cistern and the cerebellum is gently retracted, the contents of the Posterior fossa with cranial nerves five through eleven can be seen.

The Fourth International Workshop: Neurologic Surgery of the Ear and Skull Base

The Fourth International Workshop provided a continuxad ing, critical, sophisticated forum for the exchange of ideas among specialists interested in problems of the brain, cranial nerves, and skull base. Good fences make good neighbors—wrote Robert Frost. Otoloxad gists and neurosurgeons have always been anatomic neighbors but have not always been cooperative. Sepaxad rated by the posterior fossa dura—our anatomic fence—we have now joined to present this workshop, which serves as a gate in the fence. No longer must each specialty jump the fence to pick up a ball that inauvertently might have landed in his neighbors yard. We are now able to use the gate that has benefited the patient and the entire neighborhood. Acoustic neuroma surgery continues to occupy cenxad ter stage. Preoperative hearing status is not useful in the prediction of tumor size. The clinical significance of microscopic tumor remnants left on the cochlear nerve during surgery to preserve hearing will require time and careful patient observation. It is impossible to predict from preoperative studies which patients with an acoustic neuroma can be expected to have their hearing preserved. Tumor size is probably the most important determinant; useful hearing is rarely preserved when tumors are larger than 1.5 to 2.0 cm. When tumors are smaller than 2 cm, hearing can be preserved in 35% to 40% of cases. Patients with discrimination below 50% with average hearing below 50 db will probably not have useful hearing after tumor removal. The C02 laser appears to be helpful in avoiding the stretching of nerves and vessels during acoustic neuroma removal. Direct recordings from the auditory nerve offer the greatest help in allowing the surgeon to monitor cochlear nerve potentials during surgery. The use of direct nerve recordings allows a real-time evaluation of nerve function in contrast to the delayed response exxad perienced in the auditory brain stem evoked response (ABR) technique. A well-thought-out plan for the manxad agement of patients with bilateral tumors was prexad sented. Improved vestibular testing by computer looms on the horizon. This will be an important tool in evaluating patients with vestibular problems and in evaluating the results of surgical vestibular ablation techniques. Facial nerve reanimation and facial nerve palsy manxad agement produced some heated discussions at our third workshop. Now we seem to be reaching a consensus on being able to quantify the results of treatment. If the facial nerve is sacrificed during neuroma surgery, and a graft or direct anastomosis can be accomplished, this produces the best results. If anastomosis is impossible, hypoglossal-facial anastomosis is indicated. If the faxad cial nerve appears anatomically intact but no function has returned within 1 year after acoustic neuroma surxad gery, and there is no evidence of innervation, facial hypoglossal anastomosis should be done. When the peripheral facial neuromuscular system is unusable, the temporalis muscle transposition procedure was offered as the most cosmetically appealing and technically applicable procedure available. Tumors of the facial nerve present with a history of slowly progressing faxad cial weakness. If the tumor is diagnosed early, tumor removal with nerve grafting produces a good cosmetic result. However, if the tumor is treated after facial paxad ralysis is complete, return of function with grafting does not produce satisfactory reinnervation. Electroneurononography is more widely practiced in the United States since the last workshop. In cases of idiopathic facial nerve paralysis with no facial movexad ment and a 90% reduction in fiber conduction (comxad pared to the opposite side), immediate decompression of the nerve within the fallopian canal produces a better cosmetic recovery than that seen in patients with simixad lar dysfunction who do not have facial nerve decomxad pression. Critical evaluation of the results of surgery for

Silverstein Wrist Rest

A WRIST rest has been adapted to provide a supporting base for the forearm and wrist of the surgeon who is using the techniques of microsurgery and plastic surgery (Fig 1). The wrist rest provides the surgeon with a sensible alternative to supporting his hands on the patient s head or on the table during surgical procedure . It is often difficult to steady the hands satisfactorily on either the pat ient or the table. Resting the wrist on the supporting bar of the wrist rest allows the surgeon to work on delicate structures with confidence and ease. Contrary to what most people think , the wrist rest is designed for the surgeon with the steady hand. This wrist rest has been used in ear surgery, microlaryngeal surgery, parotidectomy, and blepharoplasty.